Of course it has to be the right plant for the space. Small climbers in big spaces lack impact, while big climbers in small spaces can quickly leave the gardener fighting to keep order. On the wall of a building a vigorous climber can pose a real danger to the roof if shoots get behind slates, something that is definitely worth bearing in mind before you go to the nursery and select your plant. I’ve discussed larger climbers before and you might find this information useful.

Some climbers are self-clinging, most notably ivy (Hedera helix), Boston ivies (species of Parthenocissus) and the climbing hydrangeas. These have modified roots on their stems that anchor the plant to vertical surfaces like trees and rocks, or fences and walls in cultivation. I’m going to tell you now that there’s no such thing as an effort-free climber; non-self-clinging climbers need good support while self-clinging climbers are always absolutely fine until you need to get them away from their support in order to carry out maintenance. You really appreciate just how tenacious those aerial roots can be when you’re trying to peel them from the wall, and it’s important to note that you will have to cut the plant hard back and start again from the base.

Most climbing plants will need some sort of support, such as wires, frames or trellises, fixed to a vertical surface. My preference is always to use wires because you have greater flexibility with the spacing between them and it’s easier to guide the plant to grow how you want it. Trellises and frames are easier to install, however, and certainly have their uses on smaller areas.

Climbing plants should ideally always be tied to their support, rather than letting them wrap themselves around wires or wooden slats. As climbers grow their stems expand, and this often leads to them making a congested mass of growth which can, particularly in the case of climbers grown on trellis, pull the support off the wall. The stems of wire-grown climbers can end up expanding around their wires; contrary to popular advice this is seldom fatal, but it will invariably compromise the physical strength and integrity of the stem.

When maintaining climbing plants and supports it’s also worth thinking about maintenance of the wall or fence behind. If a plant is tied to its support then it can be untied and moved away, but if the plant is wrapped around then the only way to move the plant is to sever its stems and remove it and its support.

I know we’re all busy and chasing after climbing plants – especially fast-growing climbers – is not going to be the top of our list of priorities. However it’s worth noting that time saved tucking shoots behind trellis or wire might very well end up be lost if the plant has to be severely hacked later in its life. I would suggest that tying in the shoots of climbing plants at least for the first year or two is time very well spent; if you did need to cut the plant back later to move it away from the wall then at least you have a good framework of shoots at the base to re-establish the plant.

I always use string or twine made from natural materials for tying plants in, and not for any sort of moral reason. The big problem with natural materials is that they rot and don’t last long, but that’s exactly why I use them; they usually fail at the exact point when they need to. Metal wire (including wire covered with plastic or rubber), little wire clips, plastic string and plastic ties all last for much longer, but none are forgiving if plant stems expand. By the time natural materials rot and break it’s usually time to re-tie the plant anyway. Another thing is that it doesn’t really matter if you cut string during routine maintenance but undoing wire can be slow and fiddly.

Ideally try to avoid making a simple loop of string to tie the plant to its support. A loop seldom holds the stem well unless you tie it firmly, at which point there is no room for expansion. It’s not always an issue but I find it much better to use one of two alternative methods. One is to make a figure of 8 with the string, with the plant’s stem in one loop and the support in the other. The bit where the string crosses acts as a bit of a cushion to prevent the plant rubbing against whatever it’s being tied to.

The alternative is slightly trickier but involves making a loop around the stem of the plant and then trying to the support. I find this easier on vertical shoots for some reason.

In both cases the string holds the stem in place but slightly away from its support. Climbing plants can end up taking surprising amounts of wind, and because they’re tied against a solid wall or fence the full force of the wind is taken by the plant itself. If the plant was climbing up a shrub or tree, as it would in the wild, the support and the climber would flex in the wind. The trick for the gardener is to provide enough support without tying the plant too rigidly.

It’s much better for the string to fail than the plant. It’s rare for a climber to fall off a support but not unknown, and if the string fails but the plant falls away from the wall unharmed then it’s easy enough to tie back in.

I’ve ended up with two thicknesses of string in my work box. It was just down to me not realising how thick one of the balls of string would be when I ordered it, but it’s not turned out to be a disaster by any means. I found that my normal standard-thickness string was fine for bigger stems but was cumbersome when working with thinner ones. Fate left me with a thin string and I think I’m inclined to keep using two different thicknesses; if you’re looking at two balls of string or garden twine choose the thicker one as it will be the more universally useful.

It’s not just climbing plants that can benefit from being tied in; herbaceous plants and sometimes even shrubs might need a little support. There are many different options available for supporting herbaceous plants, and I use none of them! Because I’m gardening with a low-input system I tend not to get much lax growth that needs supporting, and because I’m growing pretty robust plants it’s not a problem for me if something flops over a little. However some gardens might have a lot more plants in need of support and some gardeners might prefer to tie their plants more rigidly.

It’s much easier to provide support for herbaceous plants early in the season, but this means anticipating which will flop later in the year. If your garden is filled with plants that fall over at the first sign of rain and wind then you have underlying cultivation issues; the majority of garden plants should be able to stand up on their own. That said, a little intervention is sometimes needed.

If you find yourself having to support an herbaceous plant that’s already in full growth then the easiest way is to make a circle of bamboo canes around the base – tucked in underneath the plant if possible so it’s not too obvious – with a loop of string. Sometimes it’s necessary to tie in individual shoots, in which case using the figure of 8 method should hopefully hold the stem to its support.

Believe me when I say that I appreciate how busy gardeners are in the growing season. The numerous and various tying options offered at the nurseries offer long-term solutions that would, in principle, allow the gardener to spend less time maintaining climbers. I don’t think this is a job we should be avoiding though.

Done well, climbing plants add a lot to our gardens and I think it’s worth getting them right. I’ve spent a bit of time over the years trying to sort out problems where climbers have outgrown their supports and where supports have failed; stems being wound, or allowed to wind themselves, around wires and trellis causes enormous amounts of frustration! It might not be entirely possible to avoid cutting a climbing plant hard back to allow access to repair or replace its support, but I can absolutely guarantee that carefully maintaining a basic framework of stems will pay dividends in the long run.

A ball of string has long been a vital tool for gardeners, but as with any tool it’s important to know how to use it. Tying plant stems tightly is usually detrimental to stems, although strings and twines sometimes degrade before they constrict too much. Tying too loosely just means the plant flops around too much. I’d love to be able to give you a neat trick for getting it just right but I’m afraid it all comes down to practice.

Growing climbing plants does mean a bit more work for the usually already busy gardener, but maintenance will pay dividends if done right. If well grown climbing plants will, quite literally, take your garden to the next level.

In 1891 the Morlet Nursery, owned by Gustave Stéphany Morlet and his son Armand Charles Morlet, released a charming white rose with frilled petals called Rosa ‘Fimbriata’.

Judging by a comparative lack of information about the plant or indeed the nursery – the Morlet Nursery failed to be mentioned in Krüssmann’s epic work on roses for example – this variety failed to make a big name either for itself or its breeders. Indeed beyond the fact that one parent was Rosa rugosa and the other was Rosa ‘Madame Alfred Carrière’, little is really said about this rose. I guess that’s probably fair enough.

Rosa ‘Fimbriata’ is a quietly charming rose but is unable to hold a candle to the modern roses, and even can’t keep up with Rosa ‘Madame Alfred Carrière’ and that’s one of its parents! The other parent, Rosa rugosa, is best known as a rough hedging plant. I suspect that the rugosa actually used was probably the white Rosa rugosa ‘Alba’.

The flowers of Rosa ‘Fimbriata’ are not particularly big, barely more than 5 centimetres or 2 inches in diameter. Its perfume is light and attractive, and the flower has the palest pink flush before fading to a respectable yet uninteresting white. If the plant didn’t have double flowers with frilly edges to the petals it would have been lost to the nursery’s bonfire. It doesn’t even produce all that many flowers, especially by modern standards.

Not exactly selling the idea of this rose am I?

This is a quirky old rose for collectors of quirky old garden plants. If space is limited and you need high-performance plants then this one is not for you. If you’re making a grand rose garden this one is not for you. If your heart is set on a big flamboyant rose with a long flowering season then this is most definitely not a rose for you.

Every cultivated plant is part of gardening history. The Morlet nursery is long-gone but this little rose lives on; it has been propagated and sold or shared for 135 years for it to still be obtainable today. Generations of gardeners have seen its appeal despite competition from other varieties.

And here is the question: do all of our garden plants have to be big and showy to have merit? For some gardeners the answer is a resounding yes, and only the brightest and showiest plants will do. For others there is room for plants that need a little more attention paid to their beauty. Both approaches reflect the personal tastes of the gardener. If you’ve ever liked the idea of growing an obscure old rose then this one would be a perfectly good choice; yes the flowering could be better an ultimate height of 4-6ft, 1.5-2m, makes it more suitable for smaller spaces than some of the alternatives.

On a human level there is something to be said for plants that make us really look at them. You cannot reasonably enjoy this plant from a distance and your close attention is rewarded. The superficial dullness of this rose melts away to the point where you become far less concerned with its failures and much more enamoured with its beauty.

Oh and one last thing...

There was less of a strict adherence to plant naming in the past, so you might find Rosa ‘Fimbriata’ for sale under one of its synonyms, either ‘Dianthiflora’ or ‘Phoebe’s Frilled Pink’.

Yet again the Royal Horticultural Society offered me a pass for the prestigious press day at the Chelsea Flower Show, and yet again I let the opportunity pass me by. This wasn’t an act of protest – the Royal Horticultural Society doesn’t care if I show up or not so a protest would be pointless – or an oversight on my part. I just didn’t want to go.

I’m not a fan of crowds and the hassle of getting there from my home in the South West just wasn’t worth it. Had I been there I would have ambled around a site filled with celebrities I wouldn’t have recognised, plus the large numbers of influencers that are increasingly the darlings of a Royal Horticultural Society desperate to remain relevant in changing times. Legitimate figures of the world’s horticultural press have found themselves sidelined in favour of people like fireman-come-compost-molester (best not to ask if you don’t already know) Jonny Hinks and his fellow social media types.

The problem with the garden media establishment is that it can’t be guaranteed to put a cheery face on everything, and a cheery face is what Chelsea really needs now that its previously unchallenged supremacy is increasingly being scrutinised. People are asking questions, awkward questions, and influencers are so happy to be given V.I.P status that they will do anything to be allowed back next year.

Despite the best efforts of the Royal Horticultural Society and the BBC, the questioning and criticism around Chelsea has actually gained pace. So it should too; it’s not right that legitimate discussion should be sidelined simply because it’s The Chelsea Flower Show. If the criticisms aren’t legitimate then this iconic institution has nothing to fear, right?

If more men named Tom have exhibited on Chelsea’s prestigious Main Avenue than female designers, as has been suggested, then there are questions to be asked. Likewise we take it for granted that the elite Chelsea designers are nearly all white and firmly middle class, but is that because only white and middle class garden designers have talent? And why have so many nurseries vanished from the Floral Marquee? These are the sort of questions we’re not supposed to ask. Just smile, look at the pretty flowers and move on.

I think my favourite comment in the run-up to Chelsea was from a casual acquaintance, who said “with Range Rover as sponsor it doesn’t really feel like the show is for people like me”. I was tempted to ask whether sponsorship by a luxury hotel owned by a South African billionaire Koos Bekker, a man with an interesting family background, made it a bit less exclusive but decided not to. If you do an internet search for Koos Bekker apartheid there is nothing I can do to stop you. He’s the guy who owns The Newt In Somerset.

I’ve always been at odds with Chelsea culture. This is no slight against those wonderfully talented and hard-working people who build their beautiful high-standard displays, but is simply a comment that I don’t fit in with Chelsea’s target demographic. Chelsea is a circus and it always has been, an annual collision between the world of gardening and the super rich, the rather rich, and the people who wish they were just a little bit richer. Ordinary visitors shuffle around and try to catch a glimpse of the gardens through the crowds while V.I.Ps get invited into the gardens to see things close up. I saw a picture somewhere of a garden where a lunch party was being hosted in the garden while visitors looked on from behind the barrier. Your Chelsea show experience is quite different if you have money and connections.

Almost exactly 174 years ago Charles Dickens gave a speech to the Gardeners’ Benevolent Institution in which he said that a gardener “often knows gold and silver better as the colours of fruit and flowers, than by their presence in his pockets...”

This statement has remained true for those of us who garden as a career for 174 years, and I’m confident that nothing will change in my lifetime. Chelsea’s strong focus on gardening as an act of consumerism is very much at odds with my own views, and that’s not just because I can neither afford nor justify £4,500+ garden seats or candles at £6.50 a pop, or the remarkably small show gardens that cost more than a decent house across most of the UK. How is it the designers and landscapers get paid for their work while the planting itself is usually done by volunteers? Sorry, shouldn’t ask awkward questions.

Yes the show gardens are very pretty but there’s a certain homogenisation of styles. This is partly down to fashion and partly down to the designers choosing plants available from the same few nurseries, but also when the pool of designers is largely – very largely – drawn from the same social class and backgrounds you’re going to see a certain meeting of minds. The question of why so many of Britain’s leading garden designers come from comfortable middle-class backgrounds is an interesting one, and one that warrants reasoned discussion rather than becoming an attack.

Show gardens are impressive but are little more than temporary installations to promote their designers and, arguably to a somewhat lesser extent, the charities that have forked out serious money to pay for their services. Yes the majority of Chelsea gardens are now re-homed to new sites where their gradual decay over time will become someone else’s problem. Gardens need lots of care and in many cases the gardens as they appear at Chelsea would be very labour-intensive to maintain in their current form to a high standard over time, and as most seem to go to community groups – so often in need of resources just to exist – I’m sure the receipt of a former Chelsea show garden will become a double-edged sword.

It’s interesting to note how many nurseries have quietly vanished from the Chelsea scene over the years. A pitch at Chelsea is very expensive, and a lot of work is needed to build the display and ensure that plants are absolutely perfect. Then there’s the cost of transport and accommodation, plus cover to keep the nursery going while you’re away for just over a week. You can’t sell plants at Chelsea to recoup some of your losses like you can at other shows, and thanks to the internet the days of nurseries taking orders at the show for delivery later have largely gone. Proving the financial benefit of attending Chelsea is getting harder and harder, and a lot of nurseries have decided it’s just not worth it.

So yes, I’m definitely at odds with the Chelsea Flower Show and its culture. Am I here to launch an attack on this if not venerable then venerated establishment?

The truth is that I just lost interest in Chelsea years ago. I’m perfectly at peace that the fact that it’s more and more about celebrities and influencers each year, because that’s actually what’s important to a lot of people.

The Chelsea Flower Show needs to continue as it is. It’s thoroughly and unapologetically elitist, and that’s actually fine. Chelsea is a window into a part of society that definitely, completely and utterly exists in the UK. It’s easy to pretend that privilege and social class don’t exist in modern Britain, but both are very much alive and well; it might as well be on the public stage where it’s there for all to see. Chelsea has always been about money. Before the internet it was about bringing gardeners and nurseries together so that people could actually see plants in flower before ordering them. Show gardens allowed landscaping firms to show their skills and drum up trade. It was all a trade show for gardeners looking for goods and services. In that most wonderful gardening novel Old Herbaceous, by Reginald Arkell, Bert Pinnegar – the character whose story is told – describes visiting the Chelsea Flower Show and seeing the great and the good in their finery with their Head Gardeners walking a respectful two paces behind. Not much has really changed, although the Head Gardeners are more likely to be left at home.

The show has morphed into the celebrity and media circus it is today. I wouldn’t necessarily say that the event’s integrity has become compromised as such, but it’s a different type of integrity now. Personally I think the Royal Horticultural Society and, to a slightly lesser extent the BBC, are playing a risky game cosying-up to influencers and celebrities quite so much; wealthy people are increasingly drawn to experiences and authenticity, and want quality and substance rather than just ‘stuff’. An actor with a 30 year career on stage and screen has that quality and authenticity, but does someone phone-famous have that same appeal? There is a danger that in trying to appeal to one demographic group another becomes alienated. Maybe in these hard economic times there will be little sympathy for those who mingle with plebeians for a few days in May, but the Chelsea model is so well honed to cater for this group that it cannot, surely, risk to lose their support.

I don’t object to the fakery of it all, the rampant consumerism masquerading as inspiration, and I don’t object to the elitism either. I want there to be better alternatives.

Why do show gardens have to be expensive to be good? Why do we venerate the same few people all the time? Chelsea should continue as it is, or even become more elitist, celebrity-obsessed and consumerist. We don’t democratise gardening by dragging everything down to suit the lowest common denominator, but instead work to make sure that there are plenty of high quality gardening events to suit all levels of interest and need. Amateur and less affluent gardeners shouldn’t be abandoned to the sort of make do and mend type of ‘poverty horticulture, but should instead have access to high quality ideas, inspirations and products built around the idea that gardens are so much more than just spaces you throw money at until they look pretty. If everything in gardening has to be all things to all people it risks becoming relevant to nobody.

The Chelsea set designers won’t show any interest in making this work because they will struggle to make enough money out of it, but there are talented horticulturists and designers in the wings who would, if given a suitable platform, inspire gardeners of lesser means to create diverse, personal and exciting gardens of their own. Gardening is about so much more than spending money.

A controversial take I know. I’m sure a great many will disagree and that’s fine. We can have these open discussions in the knowledge that we’re definitely not the lowest type of Chelsea commentators.

When it comes to the Chelsea Flower Show there’s nothing worse than those people who endlessly harp on about how ghastly it all is, for whatever reasons, but are first in the queue to visit. It’s perfectly fine to not like the show or subscribe to the culture; do your own thing. It’s also fine to attend and raise questions about what you’ve observed, but if you’re going to wang on with moral arguments against Chelsea don’t then show up to schmooze and be seen by the right sort of people. Attending does not make you a somebody, and neither does it make you a better or worse gardener.

Let’s let Chelsea be whatever Chelsea is; those of us who do not subscribe to the culture should look for different icons instead.

Sure if you pay through the nose for an old olive tree that has been ripped out of its Mediterranean home, potted and shipped to your garden you can have a boring grey tree with a moderately interesting trunk. Olive trees are at home in the Mediterranean and that is where they should live. They belong in Tuscany, not Tunbridge Wells.

Few other trees really look good in a Mediterranean-style or themed garden though. The style is relaxed, a sort of naturalism but with a focus on drier climate zones. Using a conspicuously out of place tree would ruin the whole effect, but is an olive tree the only option?

I would rather grow Elaeagnus ‘Quicksilver’.

Like the olive, Elaeagnus ‘Quicksilver’ has grey leaves too. However, far from being dark and miserable, the leaves of ‘Quicksilver’ are shiny and silver. This is an important bonus in Britain, where grey and wet summers are certainly not unknown; the silver foliage is always bright and cheery.

Well I say ‘always’; Elaeagnus ‘Quicksilver’ is deciduous while the olive remains evergreen. The sight of an olive tree – definitely a tree made for summer – looking drab and depressed during a British winter is not a prospect I relish. Elaeagnus ‘Quicksilver’ comes into leaf in spring with fresh foliage.

While the flowers of Elaeagnus ‘Quicksilver’ aren’t particularly showy the perfume more than makes up for it. A sweet aroma that drifts around the garden on a warm evening in early summer... just divine.

This is a tree I really value and I’m happy to recommend to many gardeners, and not just those looking for a good tree for a Mediterranean-themed garden either; I’ve seen Elaeagnus ‘Quicksilver’ look really good in an edge of woodland garden, and of course it’s an excellent feature tree. It’s a lot faster growing than an olive tree, so you don’t have to buy a massive specimen to make an impact. Smaller trees are available in nurseries too, and you don’t have to wait long for them to grow to a reasonable size and start to contribute to the garden. If you have a particular look in mind you can train the tree as it grows too.

Hardiness-wise Elaeagnus ‘Quicksilver’ is fine for most parts of Britain, but dislikes sitting in cold and wet soils for winter. It does well in light shade but is undeniably best in full sun. USDA hardiness zone 4 and higher, but with reasonable drainage.

For those sensing a ‘but’ might be on the way, here it is: Elaeagnus ‘Quicksilver’ can sometimes decide to sucker, probably the influence its presumed Elaeagnus angustifolia parent. I’ve heard that plants raised from suckers are massively more prone to suckering than plants raised from cuttings – this would make sense – but it’s also possible that stress might be a trigger.

I’ve seen plenty of fine examples of Elaeagnus ‘Quicksilver’ over the years that have been well-behaved, but I’ve also heard stories of suckering from gardeners I trust to not exaggerate. Would I take the risk? Yes; I think the tree offers a lot and would be worth the effort of managing should the need arise. However you may disagree.

It’s not so much that this is wrong, but instead it’s only part of the story.

Firstly when we talking here about flowers we generally mean the sterile florets that make up the ‘ball’ of a mophead hydrangea and the border of a lacecap flowerhead. The true flowers are tiny and found in the middle of the flowerhead, and while their colour can change they aren’t what we tend to be looking at. Secondly not all hydrangeas can change colour; the climbing species, the varieties of Hydrangea paniculata and Hydrangea arborescens, and those with yellow true flowers – Hydrangea ‘Golden Crane’ for example – stay the same in all conditions.

The hydrangeas that change colour do so according to the presence of aluminium in the soil. In acidic soils the aluminium is more likely to be found in a form that is ‘available’ for the plants, and in alkaline soils it’s more likely to be bound up in a way that the plants cannot use. In containers the composted organic matter rarely has enough available aluminium to make flowers blue, even if the pH is well below neutral.

In the open garden things can be a bit more complicated. Just because aluminium is in the soil doesn’t mean every plant can get it, and neither is it guaranteed that all hydrangeas will receive the same dose. If your soil has a high availability of aluminium then you will get really intense blues, but if it doesn’t then the colour can be a bit faded. It’s not uncommon to see massed plantings of mophead and lacecap hydrangeas that are predominantly blue with a few light pinks mixed in. We tend to think of our soil as large areas of uniform type and composition, but in reality soil is often very variable even in a small space, with higher and lower pockets of elements and nutrients.

This variation in soil types is seen on a large scale at the Camel Valley Vineyard in Cornwall. The landowners had a specific area where not much wanted to grow. Crops were poor and grazing wasn’t great, so they planted grapes that would thrive in the conditions. The vineyard has gone from strength to strength, but it has a problem; it can’t expand because all the land around it is far less suitable for viticulture! You would think that soil across an area would be pretty uniform but that is not the case.

Drought and extremes of rain can also have an effect on colouring. If it’s very dry then the plant is less likely to be able to take up soluble elements and nutrients because there’s less water. If it’s very wet then this can, in some cases, flush things out of soil and it takes a while for levels to recover. The soil itself can also change over time too – over decades – with land management and natural changes such as the build-up of organic matter. Heavier soils are more likely to be rich in aluminium than light soils.

Hydrangeas don’t actually want the aluminium though. Aluminium isn’t of use to plants and different plants deal with it in different ways. Many just don’t take it up in the first place, while some hydranges essentially ‘store’ unwanted aluminium in their flowers and sterile florets because there’s nothing else to do with it. Where levels are low enough to not matter or where plants are able to cope there is no need for change. If aluminium didn’t exist then we wouldn’t have blue hydrangeas.

Taking the genus as a whole, most hydrangeas are white flowered. I think we could use a colourful climbing hydrangea or two, but plant breeders have yet to perform this miracle and nature seems disinclined to oblige.

Aging and discolouration happens to any flower, and hydrangeas are no exception. This process is most obvious on white varieties, where florets take on pink markings, but is not a universal trait even among paniculata and arborescens forms. ‘Vanille Fraise’ and ‘Sundae Fraise’ are two forms of Hydrangea paniculata specifically selected for their strong colouring as flowers age, but Hydrangea paniculata ‘Limelight’ and ‘Little Lime’ – a smaller version of ‘Limelight’ – start out green, open white and then turn brown and papery without really turning pink.

Hydrangea arborescens, of which ‘Annabelle’ is the best known form, starts out greenish white, goes white and then goes papery and brown. There is a nice pink form called ‘Pink Annabelle’ too, but this is a fixed colour rather than being dependent on what’s in the soil. Red mophead and lacecap hydrangeas are fairly stable; the intensity of their colouring varies – stronger where aluminium is present – but if you buy a red variety then it should remain broadly red under any conditions. That said they can fade a bit in hot and dry conditions.

You may think me pedantic for discussing this, after all the thing about some hydrangeas changing colour if the soil is acidic is broadly true. However it’s worth going the extra mile with this because some gardeners go to extraordinary lengths to try and turn hydrangea flowers blue. Usually the advice that does the rounds on the internet – and is sometimes touted by people who should know better too – is to ‘acidify’ the soil with anything from iron nails to coffee grounds and pine needles. Some gardeners swear by them, yet when these techniques are tested scientifically they don’t seem to work.

An experiment was carried out in Eastern Europe to acidify soil with pine needles. Scientists found a field with a pH of exactly 7 – neutral – and planted a forest of pine trees. To help things along they also imported pine needles from other forests to mulch the area, and they did this for 70 years. After the 70 year experiment drew to a close the soil was analysed: it had a pH of 6.9. 70 years of ‘acidifying’ soil and the pH of the soil barely changed at all.

The idea of acidifying soil is a courageous one at best. The expectation is that we can apply a modest amount of something to undo millennias-worth of soil chemistry in a short time. There is a possibility that an extraordinary amount of a material added to neutral soil would have a more profound effect, but evidence to support this is anecdotal and often little more than recycled myths. And please don’t go adding nails to your soil; firstly nails are sharp and pose dangers for anyone digging or weeding around the base of the plant, secondly nails are galvanised to prevent them rusting, and thirdly iron nails haven’t been around for decades – the nails we use now are made of steel!

Given that levels of elements found in soil are variable it’s highly likely that gardeners who appear to see effects when they try these various techniques are just seeing natural changes in fairly neutral soil. Certainly I’ve never come across verifiable information about gardeners with strongly alkaline soils being successful with any homemade recipes. I’m not going to say that it could never work because soil chemistry is very a complex thing, but I’m saying it’s unlikely.

What does work is hydrangea colourant. This is the name given to the tubs of aluminium sulphate, often with added iron, sold in the garden centres. Hydrangea colourants do nothing to change the pH of the soil but they essentially give a brief overdose of aluminium to the roots of the plant. Because the aluminium is concentrated in one place it has a better chance of getting into the plant rather than just being ‘locked up’ in the soil. You must apply hydrangea colourant to your hydrangeas at least once per year, as per the manufacturer’s instructions. Aluminium that is not taken up by the plant will, in alkaline soils, be rendered unusable fairly quickly. It’s important to note at this point that applying hydrangea colourant at too high a dose can be fatal to the plants; as I said above, the hydrangeas don’t actually want the aluminium at all!

Going the other way, turning blue hydrangeas pink, also requires a bag of something from the garden centre. Garden lime is mainly used in vegetable growing but will, if applied to the soil around the base of your hydrangeas, lock up aluminium and your hydrangeas – again we are talking about those inclined to change colour – will be pink for as long as the effects of the lime persist.

Life is much easier if we just let hydrangeas get on with it and enjoy whatever flowers they produce, but I completely understand why gardeners fall in love with the blues. Changing the colour is possible but takes a bit of effort; if you aren’t committed to applying doses of aluminium at the right time of the year then I would probably grow the hydrangeas that have no chance of ever turning blue and enjoy them instead.

One of my shrub suggestions was in fact one of my favourite spring flowering plants, a deciduous azalea called Rhododendron ‘Daviesii’.

A rhododendron and an azalea? For many decades rhododendrons and azaleas were considered by botanists to belong to separate but closely related genera. The idea that they might in fact belong to the same genus had been around for some time; Frank Kingdon Ward touched on it in his 1950 work on rhododendrons for example, before letting the side down by suggesting that other rhododendrons be split into new genera. We can all be relieved that the world of botany ignored him.

There was increasing interest outside Europe and North America in the idea that rhododendrons and azaleas belonged together. To settle the argument once and for all the species of rhododendrons and azaleas – some 1,200 species – were examined at DNA level. The results of genetic analysis not only concluded that azaleas were definitely rhododendrons but also that deciduous and evergreen azaleas weren’t all that closely related to each other. Thus azalea is now used as a common name. You can refer to evergreen azaleas and deciduous azaleas, but their formal name is now rhododendron.

So Rhododendron ‘Daviesii’ is a deciduous azalea, and it’s also my favourite. Maybe I should say that it’s my current favourite as there are a great number of deciduous azaleas around and I haven’t yet seen one I don’t like.

This is an old variety, a hybrid between Rhododendron viscosum and Rhododendron molle raised by, named by and named for, a Mr I. Davies in the 19^th century. Precisely when is up for debate; some resources suggest 1840 but the only verifiable source at the moment is a catalogue for 1869. My comment that it’s an old variety still stands of course, but I just can’t tell you exactly how old. Not that it matters; what’s remarkable is that this old variety has stood against some serious challenges from breeders over the years and yet is still popular and widely available.

From a distance its flowers look pretty much white, but when you get closer you’re rewarded with a range of colours from the peach-tipped yellow-green buds to the creamy petals, occasionally flushed pink, and the butter yellow flare. The flowers are quite slender compared to some of the more modern varieties, but they’re still big enough to hold their own in a large space.

Crucially the flowers have a warm, sweet aroma that carries on the air. This is something many azaleas do incredibly well.

Something else deciduous azaleas do well is to put up with hardship, or at least conditions that the evergreen rhododendrons tend to dislike. Once established, deciduous azaleas seem to be much more tolerant heat and drought than evergreens, and when things do get stressful they tend to be better able to recover.

Something worth touching on here is the issue of soil pH. Rhododendrons are ericaceous, and this is generally taken to mean that they need acidic soil. Truth is that it’s less about them needing acidic soil and more about them hating lime. The nuance is important because if your soil is humus-rich and around neutral – a pH of 7 – then you should be fine with most. Yes there are ways to grow rhododendrons successfully on limestone but I’m supposed to be keeping entries to the Plant Files short and to the point – this is a topic for another day. Garden rhododendrons don’t need peat. Few grow in peat in the wild so they don’t really need it in the garden; leaf litter is fine but best to avoid farmyard manure as it can be too nutrient-rich for them.

Rhododendron ‘Daviesii’ has a fairly rounded and compact habit. It grows around 1.2m or four feet tall, and maybe a little bit wider. In the UK it’s completely hardy, USDA zones 5-8. A bonus of being deciduous – aside from getting autumn colour – is that the leaves are renewed each year and you don’t get that ugly spotting you get with some evergreens.

After I published this article I was asked about whether this plant likes sun or shade, something I omitted to mention in the original text. The answer is that in most areas deciduous azaleas are usually happy in sun or shade, but in areas where summers are routinely hot and dry I would suggest light shade is best.

The best way to deal with major challenges is not to go in all guns blazing, it’s to step back and weigh up your options. You always have three ways to go: total control, compromise, and surrender. Total control nearly always requires spending time and money, while surrender means having to accept that things are as they are and that you can’t do anything to change them. Compromise means understanding what you can reasonably do, then modifying your plans and ambitions to make progress that isn’t going to cause further problems.

Problems come when gardeners don’t have resources to go in and sort things out completely but are also unwilling to compromise. The garden becomes a battleground and gardening becomes a drawn out war. Things like soil type aren’t fixed easily; you cannot hope to undo millennias-worth of geology and chemistry with a bucket of grit or some vaguely acidic organic matter, for example. There are also the gardener’s nightmare weeds, plants that spread rapidly and are persistent in the garden.

For the purposes of this article I’m focusing on wild garlic (Allium ursinum), ground elder (Aegopodium podagraria), celendine (Ficaria verna) and alkanet (Pentaglottis sempervirens) in particular, but those gardening in other areas may well have different nuisance plants. These are not ordinary weeds; these are species that have a particular reputation for their tenacity. To put it in more ecological, and dare I say honest, terms these plants are incredibly adept at survival. The allium, ficaria and pentaglottis set lots of propagules – seeds and bulblets – while the aegopodium produces vast networks of underground runners which will, if damaged, sprout new plants. Monocultures of these plants exist and yet they are seldom the largest plants around in terms of height and individual mass.

Chemical treatments of these plants seldom works. They act as a ‘hard reset’, killing the current vegetation and leaving the ground bare. Disturb that nice bare soil, with the same core conditions that allowed the previous generation of the plant to thrive, and the propagules in the soil sprout to rapidly colonise the ground again. Given how long and frustrating it can be to fight these plants it might just be easier to be at peace with your problem.

Perspective matters.

Take away fears about its growth rate and wild garlic is actually a pretty little plant. Its leaves remind me of miniature hostas, its flowers are pretty little pure white stars, and if it was a challenging species from somewhere far away we gardeners would relish it. Instead it’s a native plant with a penchant for forming vast colonies where it’s happy. It’s often found in association with another absolute thug: English bluebells.

Wait, English bluebells are a thug?

English bluebells can be every bit as thuggish as the wild garlic. Their thuggishness is so finely matched with the wild garlic that in some places they grow beautifully together as neither species can get the upper hand on the other. English bluebells will, when they’re truly happy, seed everywhere whether they’re in a woodland or a garden. The big difference between wild garlic and English bluebells is a cultural association; we’re told that a sea of bluebells is pretty and a sea of wild garlic is a nuisance, in nature or in a garden.

There’s nothing to stop us stepping back from the hyperbole and re-framing these thugs as effective spring groundcover. Celendines make cheerful constellations of yellow flowers in late winter and early spring when not much else is happening, the umbels of white ground elder flowers make pretty clouds in late spring, alkanet has flowers of piercing blue, and wild garlic makes glorious carpets of flowers that look like fresh snow.

Let’s flip the problem on its head. Rather that ask how can we get rid of these plants we ask how can we effectively incorporate these plants into our gardens.

It’s rare to have big gardens full of these sorts of plants so our initial priority is to prevent them escaping into areas in which they are currently absent. Moving plants out of the quarantine zone, as it were, risks carrying seeds or stems to other parts of the garden. We’re looking for robust plants that can hold their own against an established and vigorous neighbour.

Using plants with a main season of interest that matches our nuisance weeds moves us away from shrubs in weeds and over to planting combinations, a far more exciting proposition. We can now talk about colours because as long as the plants can hold their own against their neighbours they will be fine. If you’re working with alkanet and ground elder you might need to keep them at bay immediately around small shrubs as they get established. Let’s start with some shrubs...

I’d love to use something like the absolutely gorgeous Rhododendron ‘Mary Poppins’, with its dark new growth and warm orange flowers, or maybe the lovely pink flowered Kolkwitzia amabilis, to punctuate a carpet of wild garlic. Where conditions are right, the red foliages of Cotinus ‘Grace’ or the bold Hydrangea ‘Hot Chocolate’ would be dramatic above the sea of white flowers. You could use a pale flowered shrub but I think something with strong colour would have far more impact.

Ground elder flowers a little later, so shrub-wise I think I would go for the pink deutzias, something like ‘Strawberry Fields’ would be perfect, to produce a mass of flowers to go with the airiness of the ground elder.

Ground elder is often found growing at the foot of walls, so maybe a pink form of Clematis montana would work nicely on the wall behind. What about pink wisteria?

You could go with pinks or oranges if you’re working with alkanet. I love alkanet with red campion, Silene dioica, but I don’t think I would necessarily need to stick with pink because the flowers of the shrub would mingle with those of the ground elder. You’d do well with philadelphus I think, or Rhododendron ‘Daviesii’ for the white or pale. If you can get campion in on the action then this would make an excellent part of a colour triangle. Avoid reds though – true red flowers can be just a little dark to go with the intense blue of the alkanet.

Gardening with shrubs can be a very effective way of working with troublesome weeds. You literally bury the problem under your shrubs! Big hydrangeas and rhododendrons often have rounded shapes and are clothed to the ground, which is great, but most reasonably sized shrubs will work. Over time the nuisance weeds will be forced out as shrubs take their light, water and growing space. The biggest challenge as gardeners is to not feel that we should be sanitising the ground under them. Much as I love herbaceous plants we must never under-appreciate just what shrubs can do for us.

While woody plants will generally hold their own against herbaceous weeds, when it comes to herbaceous plants we’re looking for those that are too robust to be trusted in the average border. In a garden under my care there is an annual battle royale between ground elder and mint, two aggressive spreaders. I’ve been watching their behaviour with interest; the ground elder comes up first and seems to be suppressing the mint, but then later the mint rallies and pushes the ground elder into retreat. The two have colonised the bed they occupy but seem disinterested in conquering anywhere else; I would expect both to wander if they got the chance but they seem to keep each other under control. Crucially the mint flowers later in the summer, distracting from the decline of the ground elder. It’s not a combination I would go out of my way to make but might be an option for a gardener with a patch of ground elder and a desire to grow mint in the ground.

I’m a huge fan of Euphorbia griffithii ‘Fireglow’, which is I believe the only form grown in the UK (as ‘Dixter’ has been ruled to be meaningfully identical). The new orange growth emerging from the ground in spring is quite dramatic, and the orange flowers in late spring are pleasant. You get good autumn colour with this one too. It’s robust and easily big enough to compete with pretty much anything.

For a bit more architectural interest I would suggest rodgersias. I could quite happily collect these – indeed I once visited a collection of them at a garden in North Devon – and I’ve never seen one I didn’t like. However it is specifically Rodgersia podophylla that I would recommend. The parasol-like leaves, around waist height, are wonderful anyway but added to spring flowers – including our nuisance species – the bronze new growth adds immense drama.

Astilbes are underappreciated these days. Some are tiny and some are giants, but there are plenty that flower around waist high and will serve our needs. While astilbes will generally flower later than we need them to, their ferny foliage would interesting foliage contrasts with spring flowers. Darker-coloured astilbes tend to have darker foliage, and it’s not uncommon to find varieties that emerge with deep red leaves if that sounds promising to you. I would not recommend using any astilbe with a flowering height below 60cm or two feet, simply because the foliage would be lost against more vigorous neighbours.

I’ve found Geranium ‘Rozanne’ to be a bit of a menace in borders. Years one and two pass without incident, but by year three this plant can start to become rather large and it can cause problems with more demure neighbours. With more robust neighbours this can be very useful as the smothering nature of this geranium means that it will mingle and clamber through most things. Its flowering season starts too late to combine with spring flowers but geraniums can take over when other plants have finished. If you can get hold of it, Geranium asphodelus is a surprisingly rampant plant with little star flowers of white or pink.

If you want to cover a bigger area and don’t want to buy lots of plants then consider Clematis ‘Praecox’. This is a big and rather vigorous ‘shrubby’ clematis which will, if grown as groundcover rather than a climber, cover a lot of ground. Its blue flowers in early summer are a delight. The clematis and geraniums would work really well if you have large bare area after celandines have gone into their summer dormancy.

The problem with this subject isn’t that there aren’t many plants with the potential to look great with the rather scary garden weeds we sometimes find ourselves facing. Add those plants that will take over and use the area when these nuisance plants have died back and the list is long indeed. The key is choosing robust and vigorous plants, planting them in a difficult area with the understanding that they won’t be dug up and replanted elsewhere, and to fight the sense that these weeds are something that you must fight against.

The latter is the hardest bit; gardening culture treats it as a defeat.

The question is how much time, effort and likely money you want to spend on the problem. If the answer is not much then you have the choice of leaving an area to its own devices or doing something mildly radical. I’m all for the mildly radical. Given the level of hyperbole around certain weeds you’d think they were going to destroy the world; how come they haven’t actually done that? These plants might spread vigorously but they do so only where conditions suit them perfectly. Providing we’re not planning to replant things outside a given area we don’t need to worry about contaminating clean areas.

My advice is to get out to the nursery and treat yourself to new plants. Garden your problems away!

Read more

I never got to meet Kindon Ward – he died decades before I was born – but I would probably have liked him. His book is littered with what even now would be regarded as robust sentiments on gardening matters. He introduced the first meconopsis, the blue poppies, to cultivation but spent much of the subsequent time arguing with gardeners and nurserymen alike that it was a terrible plant, horticulturally speaking, and that people should grow other things instead.

Yes Kingdon Ward dismissed the very plant that had made him a household name. And so he should; meconopsis notorious for their penchant for death, and flowers are admired not just for the intensity of their blue but for the fact that the odds are weighted against their existence. Meconopsis are exacting in their requirements and need good care – ample water, but not too much or they will die, for example – and the have a tediously high mortality. If you like throwing dead plants out then meconopsis is the genus for you!

Kingdon Ward discussed the miffs and the mimps. As I said when I covered this idea in a previous article, “a miff he defined as a plant that struggles for several seasons and then dies (a miffy plant), while a mimp was a plant that just died without the hassle of a struggle.”

I agree with Kingdon Ward’s assertion that life is too short for plants that don’t want to thrive. Nurseries are always ready with the next novelty and gardeners have always been lured in by them, but quality shouldn’t simply be measured in terms of aesthetic appeal, it should also be measured by the robustness of the plant. I too am tempted by novelty, and sure I like to dabble with plants that are a little more exacting in their needs – it’s fun to test my skills as a gardener – but the bulk of the plants I grow are selected for their long-term performance. A garden filled with plants that need constant attention would take away the fun for me.

Blue flowers are great though. If the blue poppies didn’t hate life so much I would grow them in large numbers, but they do so I don’t. Instead I content myself with a much easier plant to buy and grow, and one that captivates me every spring.

I don’t know where people buy ordinary Centaurea montana. I don’t think I’ve ever seen it for sale, or at least it’s not really registered in my memory. I’ve seen some of the selections and forms around, and even grown a few of them; the purple-black flowered Centaurea ‘Jordy’ looks nice in pictures but makes little impact in the garden, while the differences between the white Centaurea ‘Purple Heart’ and Centaurea ‘Amethyst In Snow’ are beyond me. They’re pretty garden plants but have both faded away in my own garden.

The blue is the most robust, and it is the blue that is being added to the Plant Files. I get that the novelty forms have their place but I already have other white flowers and I don’t really want or need many black flowers.

I’d largely ignored the plant until I found myself face to face with the straight species when I was weeding in a client’s garden. That blue! I was enchanted by it. It was self seeding and I asked the client if I could take a few seedlings home. The answer was a firm no; I could throw them away but I couldn’t take any home. I did neither. I left the seedlings to grow in what was a fairly underplanted little area – why some gardeners have an obsession with bare soil is a mystery to me – and enjoyed them as they thrived.

A few months later the client gave me a tiny piece of a double flowered chrysanthemum. I didn’t really want the chrysanthemum and was about to politely decline it, but I spotted a tiny seedling hiding in the pot. The long and short of it is that the seedling at the bottom of the plant was a seedling from her Centaurea montana.

The chrysanthemum went to the great compost heap in the sky a long time ago but I still have the centaurea. I do nothing to it and it thrives. I’ve had a seedling or two in the last five years or so, but beyond that it’s been happy to just make a nice clump. It seems happy enough in my moderately heavy soil, and asks for nothing. It gets no supplementary water or feed; it just grows. Periodically a rogue rabbit comes in and nibbles it, and a few days later new flowers are forming.

It was interesting to see the Royal Horticultural Society’s trial of centaureas at Wisley last week. The plants are growing in full sun in that notably warm and dry part of England. They looked passable but nowhere near as good as in cooler and damper regions. Away from what I would describe as a fairly extreme climate region, by British standards at least, Centaura montana is a respectable garden plant. Its seeding is seldom problematic and seedlings are easily lifted and replanted, shared or discarded depending on your need and outlook.

Two things make this lovely little plant appeal to me. Firstly is the colour of its flowers. Secondly is that it seems to tantalisingly straddle the line between the formal cultivated plants and the wild looking. In a more contrived garden it lends a touch of the wild, and in a more wild-themed garden its flowers add a gentle touch of the exotic. It’s a plant to have fun with.

Centaurea montana tolerates hot and dry conditions once established, but generally is best in a reasonable soil with some moisture. I grow it in full sun but it’s seldom really all that hot and dry here; where you do get more extreme summers I would suggest growing this plant, and its cultivated forms, in light shade. It’s hardy throughout the UK, USDA zones 3-9.

The main magnolia and camellia season is drawing to a close across southern parts of the UK now, and it’s time to consider pruning. It’s a subject that has become a great mystery for some reason, yet is remarkably straightforward if you take your time.

This is the time for routine pruning, not the heavy renovative pruning that might be needed when a plant has either been damaged or has outgrown its desired or allotted space. We’ve missed the season for bold action; you can be quite brutal to magnolias and camellias early in the year, but while you might get away with it at this time of the year it’s best to do drastic action in late winter or early spring if possible. Yes this will mean the loss of this year’s flowering – and drastic pruning will likely take out next year’s display too – but carrying out work early in the season gives the plant a nice long spring, summer and autumn to break bud, make growth and for that growth to ripen before winter.

I’ve not covered drastic pruning of camellias before; it’s on my list of subjects to cover, but that list gets longer and longer and I have a full time job to do in addition to my writing. However I have covered the more formative pruning of deciduous magnolias, and you can refer to

I’ve grouped magnolias and camellias together because their routine pruning is best carried out around this point in spring. This is pruning to keep them under control where needs must. It is not compulsory to prune if you have the space to let them grow. I’m going to start with magnolias, with this advice split into two parts. Part one follows on from my previous article focussing on more severe pruning, and covers the tasks that should be carried out around 12-14 months after the major work has been carried out. Part two covers the routine pruning that gardeners might wish to carry out in order to keep a magnolia reasonably small and compact, but also the tasks that should be carried out in year three after a major prune (and in perpetuity if there is a need to keep a previously large magnolia to a more modest size).

If you have not carried out any major work then part one may or may not be of relevance to you. It depends if your tree has made water shoots; these are very long, thin, straight shoots that have not produced any branches yet. These are often produced after the tree as been damaged but can also be produced because the tree is inclined to make sudden growth.

Part One. When a magnolia has had a shock, such as a large branch removed, it will try to compensate by rapidly producing new growth to replace that which it has lost. You will typically see clusters of water shoots from each wound on your tree. The first task is to thin these out or, to put it another way, to remove shoots that are not going to be needed. Any that come from the underside of a branch are unhelpful, as are shoots clustered closely together or pointing inwards towards the centre of the tree. Choose one, two or, rarely, three strong looking shoots that are growing up and away from the centre of the tree.

If your strongest shoots aren’t facing the right way then choose the best of the shoots that are. At this point it’s more important that the chosen shoots are growing in the right direction than that they’re growing strongly. Be firm and thin out any shoots that aren’t going to do what you need them to do.

Part Two. As long and thin water shoots thicken and become woodier they can be shortened to encourage the plant to become bushier but not quite so large. Opinions differ as to how far back you should go, either a third down from the top of the shoot or a third up from the bottom. I tend not to worry too much about these rules and prune somewhere in that range. If in doubt just shorten these water shoots by half. They will break bud and produce two or three smaller shoots instead of one big one, and this will make the tree nice and bushy at a hopefully reduced height. Pruning water shoots hard will keep the tree smaller and probably more compact in habit, while pruning them lightly will allow the tree to grow a bit bigger and it won’t be quite so dense.

You can leave the water shoots if you want to, but it’s not unknown for magnolias that have been pruned hard and then left to end up taller than they were before they were pruned. In some areas, and among some growers, it’s common practice to plant new magnolias in the ground, leave them for a year and then prune the young plant close to the ground. The plant responds by producing water shoots, with the strongest shoot allowed to grow up un-pruned. In principle you can get a large tree in a much shorter amount of time. I must say that I’ve never been brave enough to try this technique.

The advice above assumes that you have carried out, or need to carry out, fairly substantial pruning on your magnolia. There are times when a far more subtle approach is needed. If you need to reduce your magnolia by up to around 30cm, a foot or so, then you will be pruning smaller branches and the technique is to simply follow each major shoot back to one or two junctions, where side-shoots break from the main branch, and cut above that shoot.

This is very similar to the routine pruning of camellias. Like magnolia branches, camellias produce long stems that branch out into smaller stems. Lightly pruning a spring flowering camellia simply involves tracing a stem down from the top until you find a side branch around the level you want to prune, then cut there. It really is that simple, although there is one thing to watch; the side shoots towards the tip of the stem face outwards at around 45 degrees, but further down side shoots tend to splay out at a wider angle, closer to 90 degrees.

The aim of any pruning is to keep the character of the plant but at a smaller size. You could run a hedge trimmer over a camellia and clip it into a weird shape – the plant will be fine but will lose its natural form, plus you lose all rights to complain about lazy and unrefined pruning in gardens. Camellias are remarkably forgiving compared to some trees and shrubs; they’re a good plant to learn the art of pruning and shaping with; as long as you’re sensible you pretty much can’t go wrong. However if you need to do a very hard renovative pruning – let’s say taking more than 60cm or two feet off – you’re probably best holding off until late winter to carry out this work. I will endeavour to write a how-to article when the time is more appropriate.

All of this assumes of course that you have a big camellia and want to make it a bit smaller. If you’re starting with a small plant and you want to keep it fairly small and compact then you will want to pinch out the tips of new shoots. After flowering the plant will make a flush of long, fleshy shoots; these may be red or green and will grow to around 10cm or three inches in length, depending on variety and on growing conditions. Once these shoots have reached this sort of length use your thumb and forefinger to break off the tip. This will stop the plant making its second flush and to produce new side shoots, reducing its rate of growth and encouraging it to grow more compact than it would if it was left to its own devices.

Plants deserve our best. I’ve earned a good reputation for my pruning skills and with these fairly basic principles you can master pruning magnolias and camellias too. Not just light titivating either, the real structural pruning too. I can skim over a camellia around my height in around five minutes, maybe less, but I’ve been pruning camellias for 20 years. And not just one or two camellias over that time; with my nursery years and my time as a professional gardener we’re talking about tens of thousands, from young plants ready to go out for sale up to big old specimens in gardens. Be patient. Take time to consider your options, how you want the plant to look and where you should cut to achieve that

Camellias are more forgiving than magnolias. Magnolias tend to overreact and go a bit haywire when their structure is pruned, but camellias just get bushy.

These are principles, not firm instructions. Every magnolia and camellia in single garden is unique in its way. Your needs as the gardener will vary too. Some of you will have read this article with mild interest but will be happy for your magnolia and camellia, or multiples of either or both, to grow as nature intended. For those who are a little concerned about plants getting too big, maybe because they’re in the wrong place or have grown bigger than anticipated, I hope this will give you the confidence to make adjustments.

I can’t give you certainties unless I’m looking at the plant in question. In the future I might be able to ‘beam’ myself over to your garden to help you, but until then you’re on your own. You’ll be fine as long as you take the time to think things through before you start pruning. Making the first cuts can be daunting but as you get into the rhythm of pruning woody plants it all gets much easier. It’s very rare for a plant to be pruned to badly that it cannot possibly be recovered – this is not an invitation to try – but it may very well be necessary to go back at a later date to carry out further work.

And this above all is the overriding thing about pruning. Most books and advice treat pruning is a fixed task that you begin, carry out and complete in one sitting. A one-off thing. No, pruning is about ongoing interventions. Sometimes you leave your plants alone, sometimes you make a few adjustments, and periodically you must intervene in a more drastic way. You do not have to complete pruning operations in one go. You can prune a few bits, come back in a few days and do a couple more after you’ve looked at the plant a few more times. You can prune a bit this year and, providing your plant looks OK, come back next year to do more.

The more you prune the more confident you will become, and the more you will be able to interpret the structure and behaviour of plants. Magnolias and camellias have reputations for being difficult to prune properly, yet some gardeners choose to brutalise their plants with machinery. If the plants can cope with that then your careful and considered pruning will be just fine.

The most iconic is Rhododendron ‘Cynthia’, a Victorian hybrid of such ferocious pink that its flowers jar awkwardly with nearly anything. Grow Rhododendron ‘Cynthia’ with the electric blue of a carpet of bluebells and you’ve got one of the most exciting combinations you will ever see in the garden, but the strong pink of ‘Cynthia’ just clashes with anything else flowering at the same time.

The Japanese azaleas can pack a punch too. Some of the colours are so intense that they become difficult to photograph. Do we really need such intense colours?

Spring is no time for modesty. We’ve endured the gloom of winter and now is the time we can embrace those colours most of us would steer clear from in the summer garden. A few weeks of outrageous colour won’t cause us any physical harm and, done properly, injects a bit of vitality into both gardens and the very season itself. I say it does no physical harm; I find staring at the brighter pink azaleas causes me a little discomfort in my eyes. Not enough to not enthuse about these plants of course, but if I look closely at a bright pink azalea on a sunny day for more than about 20 seconds I find it a little uncomfortable. I admire them for this; I haven’t noticed this with any other plant!

In a matter of weeks the display will be over and good taste will return to the garden.

It’s a rhododendron of extraordinarily bad taste I’m adding to the Plant Files this week. Rhododendron ‘Point Defiance’ was raised in 1970 by Norwegian born Halfdan Lem, a breeder of several iconic American rhododendrons and who became famous for his giant-flowered Walloper Series.

‘Point Defiance’ is an extraordinary rhododendron. From a fairly unassuming plant comes robust trusses of giant flowers of gaudy pink and white. There are other rhododendrons with large flowers of course, like the ever-iconic perfumed ‘Loderi’ hybrids, but these are a little delicate and need a little shelter. It’s a small tragedy that the giant white and luminous pink flowers of Rhododendron ‘Point Defiance’ aren’t perfumed, but to my mind it makes up for it with the size and colour of its flowers.

It’s bright and it’s brash to the point of almost being offensive: I love it!

I greatly anticipate its flowering season, absolutely love it when the flowers are open, and yet am wholly relieved that it doesn’t flower through summer. To have something as outrageous as Rhododendron ‘Point Defiance’ in flower during the summer would be a crime against moral decency in gardening.

This rhododendron is somewhat rare in cultivation, at least here in the UK. It’s not particularly difficult to propagate and grow, it’s just not something the nurseries like to favour. I suspect it looks ghastly in a small pot. Garden centres and nurseries are beauty contests for plants; only the prettiest plants get chosen. I know it’s just how things are now but I also feel it’s a bit of a travesty, especially for gardeners who have a larger garden to fill and want something a bit different. Plant breeding seems wholly focused on small and compact plants that look good at the point of sale, and it seems those with larger gardens are just expected to plant more of the same thing to fill the space. Gardeners are denied great plants – or are forced to search for them in specialist nurseries – because they don’t present well for retailers.

I’m not here to dictate standards of taste and decency. I love ‘Point Defiance’ and you may well hate it. Love or hate, I think we can respect the fact this plant does have remarkable conviction to its cause, and that the gardening world is richer for having these more challenging colours even if we don’t choose to grow them ourselves.

Rhododendron ‘Point Defiance’ is perfectly hardy for the UK, USDA zones 6-8. Usual caveats for rhododendrons about neutral to acidic soils that don’t get too dry apply, although ‘Point Defiance’ is defiantly resilient compared to some rhododendrons.

The most challenging thing seems to be finding a nursery that sells it.

If clients choose to watch Gardeners’ World on a Friday evening then that’s perfectly fine. Many people do; some find it interesting and instructive, others find it gentle and cathartic. You may by now have deduced that I do not watch Gardeners’ World myself. Nobody is forcing me to, even though I am a gardener by trade. Sometimes people are surprised that I’m not glued to my television screen watching with bated breath as Monty Don ambles around his garden telling viewers how to sow sweet peas and when to plant out the cosmos.

It’s not for me, and it’s not for gardeners like me. Gardeners’ World to me is like what watching a daytime cookery show is to a chef. Sure I might learn something, but generally speaking the whole thing will be numbingly dull.

My interests have moved on from that sort of gardening. I used to love Gardeners’ World – Geoff Hamilton in my day – but over time I moved on from what it offers. I’d learnt how to divide perennials and sow sweet peas; I wanted more. That’s difficult for what is essentially a light-hearted garden-based entertainment show. Gardeners’ World is not, and does not claim to be, particularly educational. It’s an amateur gardening show aimed at amateur gardeners, not at irritable professional gardeners.

So why do I charge clients £10 if they mention Monty Don?

It’s not about power and influence in the garden, and neither is it because I personally cannot stand the man. Monty Don is, in my eyes, an actor who has made a very successful career pretending to be what I am. It irritates me that he is revered as being some sort of all-knowing gardening deity. He is careful to keep himself on familiar territory rather than pushing the boundaries of his knowledge and abilities, and periodically lashes out in the media against professional gardeners and horticultural experts who threaten his delicate ego.

But that’s my opinion and not why I charge the £10 fine. My issue is with the idea that a celebrity gardener is somehow able to dictate what is right and wrong in the gardens under my care. He cannot possibly hope to understand the nuance of microclimate and soil types, or how plants grow in my area. Neither does he care. Monty Don is a generalist spouting general ideas to a general audience. I’m working with specific people in specific places, and it is my job and my obligation to provide accurate and appropriate information tailored to the gardens in which I am working.

Having a client say “Monty Don said...” is unhelpful. It encourages clients to think should aspire to a garden like Monty’s, and that they should do what Monty instructs them to do. I on the other hand want clients to have gardens that reflect them and work for their needs. I want them to grow the plants they like, subject to suitability, in ways that bring them pleasure.

This sort of generalist approach is not restricted to Gardeners’ World. It’s found in gardening books and magazines too. It would be impossible to create any form of media that is truly honest about gardening; I try here but even I must resort to general principles. Every Tuesday I add another plant to the Plant Files, and I’m grateful to all who read them. Some plants you will like, some you will not: this is fine because you’re free to choose which ones appeal to you. When it comes to the minutiae of how plants perform under certain conditions and how to look after them there is absolutely no way that I could give you anything more than honest general guidance. Treat all gardening media, even my articles here, as guidance and not firm rules.

But that’s not how Gardeners’ World works is it. Viewers tune in to be instructed by someone they perceive to have great wisdom and expertise, when in truth they’d get just as reliable information from their postman. It’s not all Monty’s fault; it has clearly been decided by some TV bods in a conference room somewhere that nobody would watch a 30 minute programme that looks at the comparative benefits and disadvantages of different types of string for tying up plants.

What gardeners need, so these people have decided, is nice easy bite-size chunks of information delivered in a gentle TV magazine show.

But what of those gardeners who want something more? According to the BBC and the Royal Horticultural Society such people don’t really exist, or if they do then they exist in numbers too small to be significant. Those of us who have ceased to be amateur gardeners are left to fend for ourselves; there’s no popular media for us, and we must either find solace in the specialist interest groups like the Hardy Plant Society or the Rhododendron, Camellia and Magnolia Group, or we go it alone.

I think that’s a real pity. I truly believe that gardening is a journey, one where we start from humble beginnings and learn as we try to build gardens that bring us joy. Gardens are forged from the successes and failures of their gardeners.

There is definitely such a thing as too much information. There’s so much information around, and relying on different sources can be baffling when often contradictory advice is given. Gardening has become far more complex in recent decades, but I would argue that the answer is to encourage everyone to build their own knowledge and to gain their own experience rather than trying to simplify everything to the point where it lacks meaning. The range of plants available to us has expanded considerably, and the ways we grow them have moved on from what could be called the ‘old principles’. In addition the openness of the internet allows for a greater sharing of information between gardeners, but has the arguable downside of allowing anyone with internet access to call themselves a gardening expert and say whatever they want.

My advice for gardeners just starting out is to find one source of information and stick with that for the first year or two. You will quickly find inaccuracies but that’s OK, but at least it means avoiding the challenges of different sources telling you what to do and how to do it. A great frustration I personally feel is that a good amount of the advice being dosed out is based on old ideas that have largely been debunked, or at least where our understanding has moved on. Our understanding of plants and gardening is always changing, but there are those who fail to keep up when they really should.

About 15 years ago the Royal Horticultural Society quietly sidelined research that concluded the age-old practice of teasing roots out when planting was not just pointless but can actually slow down the establishment of several plants. The research was important because it answered the question of whether you should do anything to adjust root systems of potted plants – you should not unless the plant is very rootbound – but this was unhelpful to an organisation making a lot of money publishing gardening books telling gardeners how to plant things. People might return their books and ask for refunds!

I could cite the example of Monty ‘The Nation’s Head Gardener’ Don telling gardeners to go and deadhead their daffodils so that they don’t waste their energy producing seeds. This has been debunked widely, not least of all by anyone who doesn’t bother yet still has plenty of flowers each year. The hybrid daffodils most of us grow don’t really produce many seedlings anyway; when was the last time you discovered daffodil seedlings popping up in the garden, or found that your clumps of single varieties had been infiltrated over time by inferior seedlings? Daffodils ‘wasting their energy’ implies that they’re weak plants struggling to survive and is total nonsense, but despite being an idea that no longer holds up to scrutiny it’s still dosed out by people who frankly should know better.

There’s a guy on social media calling himself Dave The Plantman. He’s a marketing manager for a major British rose nursery, and has branched out into sharing the wisdom of his 40 years in horticulture. Over 317,000 people follow for his pearls of wisdom. I use Dave as an example of how simply doing a job for 40 years isn’t itself good enough; his content is friendly and amiable yet littered with errors. Most of what he says is broadly true – his tagline “interesting fact” sometimes verging on woeful inaccuracy – but there are often things that are either no longer true or even have never been true. He’s not double checking what he’s saying for accuracy before doing his videos, and he’s clearly not keeping up with changes to horticultural understanding. I’ll say it again: doing a job or working in an industry for 40 years doesn’t make you an expert if you’ve not kept up your learning.

There’s a strong sense of it’s only gardening so it doesn’t matter though, but people spend a lot of time, effort and money on their gardens. Gardeners deserve the very best, even if that means inconvenience for those of us who choose to stick our necks out and share what we know. It seems to be a widely held belief that all gardeners are first-year novices who know very little, and there is a huge amount of effort focused on such gardeners. It would be catty of me to suggest for a moment that a number of gardening’s superstar figures aren’t truly experts in the sense that we might hope they are, but are instead personalities who know fractionally more about their topic than their audience. No, that sort of sentiment should be kept for an article about social media influencers.

Maybe the majority of gardeners really are happy to just do a few bits and pieces here and there. That’s perfectly fine, and as I believe strongly that happiness is a key part of gardening I’m happy to go along with that. However there are those who will invariably want to know more. There was a time when you could saunter along the path from novice to expert at a pace dictated by inclination, but now it seems the gap between amateur gardening and expertise has become a great canyon. This polarising of gardening culture, coupled with the decline of the gardening communities that used to help individuals develop their interests, almost seems weighted to keep ordinary gardeners in their place. There’s no longer a sense that if you wish to learn more about gardening that you should be able to, and I think this is a real pity.

My obligation to my clients is to do my very best for them. This means working hard to improve my knowledge and skills, not only answer their questions but able tailor answers to their specific conditions and needs. I put enormous effort into the work that I do and maintain high levels of accountability for what I say and do. I simply cannot put up with endless rounds of Monty said we should do this.

Blindly following instructions from some distant figure would make my life much easier, and would mean that errors of judgement could be deflected onto someone else: Monty made me to it. That would make me a terrible professional gardener though, and is something that I must avoid at all costs.

And that, dear reader, is why I charge a £10 Monty Don tax.

Such is the notoriety of the deadnettles for spreading rapidly that few gardeners would even consider deliberately adding them to a garden. Yet it’s not all that unusual to find some absolutely lovely plants in a genus of weeds. Take oxalis for example, a plant notorious for its aggressive seeding and for being difficult to eradicate; in the genus there is the lovely Oxalis tetraphylla ‘Iron Cross’ that’s used in containers, and I’ve seen the red and white flowers of the ‘candy cane’ Oxalis versicolor on the bench at respectable flower shows.

One species of lamium is a truly lovely woodland plant, Lamium orvala.

It looks more like a nettle than other cultivated lamiums, yet is about as polite a plant as you could wish for. It bulks up gently to make a pleasant clump, but there’s rarely any seeding to worry about.

I know there are very few forms in cultivation, Lamium orvala itself and the white flowered form ‘Album’ are fairly widely available in nurseries, and I’ve heard of a form called ‘Silva’ which has the typical pink flowers with a silver stripe on the leaf.

Lamium orvala ‘Album’ is a little more compact and demure than the pink, its white flowers shown off against paler green leaves. You can tell the two apart by the foliage alone as ‘Album’ has leaves of fresh green, while those of the straight species are darker with a purplish hue.

It’s the pink form I prefer. Granted I would prefer the pink flowers against the paler foliage of the white form – we seldom get all we want.

What I like about the species itself is that it’s good and robust yet eminently suited to even the finest garden. It has that hint of the wild about it but in a form that is morally justifiable to recommend for the majority of gardens.

Indeed if you want a large drift of this lovely plant – something I would encourage if you like that plant and have space – then you must either be patient and divide your plant or buy several from the nursery.

Lamium orvala is happiest in light shade, in soil conditions away from extremes of dry and wet. It will cope in full sun if it’s not too dry at the roots, or in deeper shade, but won’t be as good. I would expect ‘Silva’ to be every bit as robust as the species but suggest that ‘Album’ might deserve a little more care. That said, my Lamium orvala ‘Album’ has been ignored and neglected for years and seems happy.

The species and its forms are perfectly happy across the UK and are apparently trouble-free. USDA hardiness zones 5-8. In the US I would be mindful of a moderate potential for seeding in the warmer regions; it’s not done it in the UK but keep an eye on it.

It will also explain why I neither promote nor condemn either.

Glyphosate is a harmful broad-spectrum herbicide. It kills things. It’s not good for you and me, it’s not good for our pets, it’s not good for wildlife, and it’s sure as hell not good for plants. It’s become the go-to product for weed control largely because it’s considerably safer than alternative products that cause even greater amounts of ecosystem damage and danger to the life of quite frankly anything, user included.

Being safer does not mean safe. Glyphosate will likely, in sufficient doses, increase your chances of developing various cancers. The lethal dose of glyphosate for people is ridiculously high, but prolonged exposure even to fairly low doses is still potentially harmful. Glyphosate is used as a desiccant to dry wheat ready for harvest, wheat that then goes into the food chain. It’s also used in agriculture to kill areas of weeds and even whole fields of grass before ploughing. Its use in gardens is considerably less, but by being used widely in gardens there is greater risk of direct contact between people and large doses of the product.

What’s quite interesting about glyphosate is the differences in rules and regulations around the handling of the concentrate. To clarify, the concentrate is added to an amount of water to create the herbicide. The herbicide, concentrate plus water, is what is used to kill the weeds. To use a food analogy, a concentrated fruit drink is added to water to make the drink itself; you add it to water but you don’t drink the concentrate.

In the UK glyphosate as a strong concentrate is primarily only available to those who have undergone training and received their formally recognised PA1 ticket. The old days of grandfather rights, where anyone born before a certain date can buy and use any product, have been phased out. To handle the concentrate as a qualified professional you must wear chemical-proof gloves, face protection, chemical-proof boots and chemical-proof outer clothing. This is because it’s understood and accepted that you’re handling a hazardous chemical.

You’re also obliged to keep members of the public out of your spraying area, and it’s assumed that this applies to animals too. You need special extensions to your qualification if you’re applying herbicide within 2m or 6ft of drains, ponds and watercourses, and you have an obligation to apply glyphosate when the windspeed is below 4mph, temperatures are neither too cold or too hot for the herbicide to be absorbed, and there is no rain forecast within six hours.

Not of course that everyone sticks to this; I passed a guy spraying a car park a couple of weeks ago on a windy day. He was in a protective suit but no effort had been made to keep the public away. How does that not raise questions with some people? Anyway...

In the US the regulations suggest that you might want to wear trousers while spraying.

Seriously, the same bottle of glyphosate has a completely different label for the largely regulation-free USA! Is it any wonder Beyer Crop Sciences, who bought Monsanto many years ago, are facing legal challenges? They could label their product to strongly suggest a robust approach to safety, both human and environmental, but choose not to. Home gardeners in the UK have access to reduced concentrations of glyphosate, either as a ready-mixed product or a sometimes as concentrate. Contrary to rather common belief – at least among those who periodically try to pester me into parting with ‘the good stuff’ – the higher concentrations don’t mean that the resulting herbicide is stronger; it isn’t. The higher concentrations used by qualified contractors mean you need to use less of the concentrate in the same amount of water to do the same thing. If something is twice as concentrated then you only need to buy half the amount. Glyphosate that’s applied in too strong a concentration is useless. It burns the leaves without getting to the roots, so not only do you need to apply the product again you’ve also dumped a load of a hazardous product onto your path, drive or soil.

It’s not difficult to see how people have become concerned. The substance is dangerous and there are horror stories, particularly coming out of the US, that should make anyone pay attention. Concerns around the human and environmental impacts of glyphosate have pushed gardeners to explore other options. Recipes involving salt and vinegar, condiments for us humans, are freely shared online. I’ve just finished a packet of salt and vinegar crisps, so these ingredients must be perfectly fine for the environment, right?

Vinegar isn’t just vinegar. There are different strengths for different purposes, depending on how they are made and the concentrations of acetic acid. The vinegar used in food is usually around 3% to 6% acetic acid, while the cleaning grade vinegar deployed against weeds is around 15%. Consuming this vinegar as it is will leave you with some pretty unpleasant symptoms. There are stronger vinegars, for professional agricultural and horticultural users only in the UK, that need to be watered down to get to 15%; I used one years ago that caused my fingerprints to peel off when I got it on my hands. Great if I wanted to commit a burglary, not so great if it got into my eyes.

The big appeal with vinegar is that it’s a ‘food’ product, so most gardeners would assume this means it’s safe for insects and so on. Yet a vinegar concentrated enough to burn leaves will kill or massively harm any insect unfortunate enough to come into contact with it. Strong vinegar is used to sterilise and will perform this function in soil too. Fungi and other microorganisms don’t stand a chance, even though the vinegar is inevitably dispersed through the soil when it rains. Yes there comes a point where the effects dissipate completely, but regular use of strong vinegars is going to cause serious problems to the soil ecosystem.

The other recommended ingredient is salt. The idea is that it dries plant tissues out and kills, or at least damages, the weed. While salt doesn’t come in different concentrations it does still pose a risk to the environment. It’s more persistent in soil than vinegar so its effects last longer and cause greater harm; history is littered with stories of salting the earth so that enemies can’t grow their crops. Yes we’re talking about vastly different amounts of salt, but then we’re also talking about harmful effects at a microscopic level. Gardeners near the sea will know how damaging lots of salt can be to garden plants, yet they still have to contend with weeds!

The doses of salt and vinegar, and the regularity with which they are used, for weed control are far greater than would be safe for people to consume, yet both are advocated by organic and chemical-free gardeners as weed killers with no harmful effects. I don’t know whether it’s naivety, stupidity or the belief that anything challenging their narrative is fake news, but you really would have thought the those advocating to prevent harm to soil fauna from glyphosate would be keen to avoid harm to soil fauna by other means. If the doses used would cause harm to adult humans then they’re not going to be safe for smaller organisms.

Ah yes, but what about soil persistence? This is a great question. One of the big issues around glyphosate is that it can persist in soil. I’ve not been able to find reliable information about its persistence; manufacturers seem to be claiming that it’s not persistent in soil while those campaigning against it seem to be simultaneously claiming that it stays locked up in soil while also claiming that it’s leaching into watercourses. I know Britain’s Environment Agency monitor glyphosate levels in rivers as a routine, and indeed part of the PA6/aw certification is about informing the Environment Agency of what product you’re using, and where and why you’re using it.

The challenge is that soil persistence – how long something stays in the soil – depends on several factors. How much absorbent organic matter is there in the soil? Is the ground irrigated or rained on, which will wash something deeper into the soil? It’s best to assume that there will be negative effects and mitigate against them.

Which is why there needs to be a raising of awareness around the risks of using industrial strength vinegar and large amounts of salt in gardens. The effects might not be instantly visible but we are still only just starting to understand the benefits of soil fauna and we need to be every bit as cautious with home remedies as we are with synthetic chemicals.

This is where I’ve fallen out with organic gardening. I’m not here to advocate for synthetic chemicals in any way, but for me there is a huge flaw in the direction of supposedly environmentally friendly gardening. The business of killing things in the garden is a dirty one, and the over-reliance on synthetic chemicals has been replaced by an over-reliance on non-synthetic options. When it comes to slugs and snails, sap-sucking insects or weeds, organic and home-brewed options are still about shortcuts to changing our environment in ways that are inherently harmful to natural processes. Modern organic gardening seems focused on maintaining the status quo and doing conventional gardening but with products that give the illusion that we’re not doing quite so much damage as we would if we were using synthetic chemicals. Given that many of the organic-approved and supported solutions to garden problems need regular reapplication I would say it’s fair to suggest that the gap between the harm brought about by occasional use of even the most harmful synthetic chemicals and the regular use of things like strong vinegar is likely to be unnervingly narrow.

This is why I advocate for a certain type of gardening. Trees, shrubs and perennial plants grown in relative density to create a sort of artificial habitat, lawns instead of paving to reduce the need to care for hard surfaces, and wherever humanly possible taking inspiration from natural processes rather than simply following gardening scripture dosed out by approved parties. On a personal level I like that sort of gentle gardening that comes from guiding what’s happening rather than constantly imposing my will, while on a commercial level I simply cannot maintain high-input gardens for clients who only have me – usually can only afford me – for one day a fortnight.

I advocate for the responsible and careful use of any and all products intended to kill. Any herbicide, insecticide or fungicide we use in our gardens represents a failure to do better. Sometimes it’s a failure to grow plants in a way that encourages them to be robust enough to withstand problems, or it’s a failure by growing plants that are sufficiently outside their comfort zones that artificial inputs are needed. In the case of weeds and hard surfaces it can be a failure to properly maintain a surface, or the failure to accept that we’ve reached a state of existence where weeds have become our enemies. The majority of weeds offend our aesthetic values but do not meaningfully constitute a major problem.

We’ve also been lured into the belief that we can maintain high standards of tidiness without having to invest time and effort.

Reaching for a substance of any kind should always be the very last resort, after all other options have been exhausted. This shouldn’t really need saying because deep down we know it’s the right approach to have, but too many gardeners treat organic and synthetic interventions as time savers or simply the first and only option.

I know the gardening community favours compliance above all things, and that not falling in line with the salt and vinegar crowd puts me in a difficult spot. I believe passionately that gardeners of all levels of ability should be encouraged to think and reason for themselves, not to simply follow the words of anyone and everyone with implied status. I’m here to say that there are no herbicides we can use with impunity, and that all of our actions and decisions in the garden have consequences whether we mean them to or not.

It’s a noble ambition to garden without having any sort of negative impact, but it’s a wholly impossible one. Gardening of all kinds is about imposing our will on an area of ground, whether we accept that or just pretend that we’re doing a jolly good thing to benefit the wider world. I wonder if the path of enlightenment in gardening isn’t simply to accept that we leave footprints, and focus on leaving the lightest footprint we can?

I get a lot of pressure to be heavy handed with herbicide from clients who cannot abide the idea of a single weed on their sea of gravel. Theirs is an issue of ideology and not horticulture, so I resist. With other clients I might get the sprayer out every four or five years when things have reached a point where there is a definite need for a reset. The priority must be to reduce use of every input, not just swap one environmentally dubious option for another. This is why I discuss chemical use on the Pen And Trowel Substack without condemnation; I would rather encourage good decision making and a desire to find better ways to manage gardens rather than just crashing down on anyone who doesn’t do things my way. Encouragement, not admonishment.

But we should try to approach gardening as more than just a series of problems for which we need solutions, and instead create gardens that avoid having problems in the first place. This comes from thoughtful gardening, not from a spray bottle.

The farm shop is currently running a honeytrap for local influencers.

Influencers are a notable pest species in the UK. Their numbers are increasing at a worrying rate, and while they used to be a pest of restaurants they’re now increasingly becoming a pest of gardening too. The local farm shop has grown around half a million tulips in a field around the back to attract the influencers, presumably to keep them away from the others crops. It’s like companion planting but for a larger and arguably more bothersome pest species.

While the influencers were ambling around in the tulips and having their photographs taken, other places locally were comparatively influencer-free. The farm shop hasn’t managed to control the numbers but has reduced the nuisance they cause by keeping them busy in one place and taking some of their money off them. Those adventurously priced pots of tulips were flying out.

Of course seasoned gardeners won’t have been drawn to the lure. We know we can get a lot more tulips for a lot less money, but for those who don’t know these pots are a bit of immediate colour with little effort. The tulips will lose their flowers in a matter of days and will be thrown away.

It’s got me thinking about how the journeys into gardening are changing. It’s probably fair to say that most of us ended up with a bit of space for one reason or another, and a lot of our plants came to us from friends and family members in those early days. It’s a good way to start; we might have had a vague idea of what we like but very little clue beyond that. We ended up with a jumble of plants, but that’s fine because we were just learning. Over time we lost certain things because we decided they’re weren’t what we wanted, and we bought new things that we liked.

Indications are that the new generation of gardeners is focusing far more on instant impact rather than accepting hand-me-downs. Whether that’s because there isn’t necessarily that culture of sharing plants now I couldn’t say.

One key plant I was given during my early days was Geranium macrorrhizum. It was given to me by my parents because it was tough, easy and they had plenty to share. Geranium macrorrhizum is one of those plants that sooner or later you need to thin out, so it’s a great plant to give to other gardeners.

I still grow this plant but not just out of a sense of nostalgia; Geranium macrorrhizum is a valuable plant in the gardens that I care for. I love its resilience and willingness to densely carpet ground under trees and shrubs – interesting that I’ve never known this plant to seed around – even thriving in difficult areas. Its strongly scented leaves seem unappetising to rabbits and deer.

In short Geranium macrorrhizum takes care of difficult areas for me so I can go and look after the rest of the garden.

Its dark pink flowers aren’t borne with the same profusion I like to see from other geraniums, and its leaves are pretty enough without being all that exciting. It’s very helpful to have a plant I can propagate by quickly breaking a piece off and planting it where I need it.

I’m referring here to Geranium macrorrhizum itself, the species as most commonly encountered in gardens and nurseries. There are other forms around – lighter pink or white in flower, and even a variegated one – but these are not quite so tough and resilient. A good rule of thumb is that the lighter the flowers the less tolerant of drought and neglect they are; white forms like ‘White Ness’ need decent garden soil and are definitely not vigorous. Don’t know why anyone would bother with the variegated one at all...

This is not the most desirable geranium by a long way. I would go as far as to say that nearly every cultivated geranium is probably going to be prettier than reliable old Geranium macrorrhizum. Mean, maybe, but this plant is more useful than desirable. Those plants that can be left to mind their own business while we tend other areas are stalwarts of the larger garden. We can’t be everywhere all the time, and filling a large garden with plants that constantly need attention is a recipe for trouble.

Geranium macrorrhizum is hardy across the UK, down to USDA zone 3, and while it’s not keen on permanently wet conditions it is remarkably tolerant of drought once established. It seldom reaches much more than 30cm or a foot in height, but will spread indefinitely if not curtailed. On an island border or tree circle surrounded by lawn it won’t cross where it’s mown down, and if there is a need to curtail its spread elsewhere this is easily achieved by occasionally running around the edge of the clump with a spade. Where the plant is frequently propagated for use elsewhere this will slow its spread.

Share

I love spring but wish it wasn’t so frantic. The grey of winter sapped every bit of my energy; it takes a great deal of effort to keep going through seemingly endless dismal days, not only keeping spirits up but also fighting the urge to hibernate in a warm spot. With a good supply of chocolate cake...

But spring is spring, and as with all other seasons it does what it wants with no regard for the sensibilities of the gardener. Every year I promise myself that I will get out to enjoy the dazzling displays of rhododendrons, magnolias and camellias, plus all the lovely bulbs and herbaceous plants that grow under them, and every year something comes along to thwart my efforts.

Life is like that though.

I recently spent a very enjoyable time in the company of someone who... well who isn’t really a gardener as such. Her knowledge of gardening ran to “this is pretty” and little beyond, and yet I found the encounter wonderfully invigorating. No lofty discussions about whether this plant is better than that, or how to blend colours.

No, just enthusiasm.

What was really telling to me was how we looked at the same magnolia and saw different things. I saw a magnolia that has nearly finished flowering, and was disappointed because its few remaining flowers were nothing to its peak display, while she was happy that there were flowers there at all.

It got me thinking about my relationship with gardens. Because I do what I do, I tend to view gardens as puzzles to be solved. I get so caught up in analysing what is good and bad about a garden, and what needs doing and what’s done well – not just in gardens I’m responsible for but also those I’m visiting – that I’ve lost track of priorities.

I was going to talk about the challenging relationship between gardening and chemical use today; that will save for another day.

This week it’s all about joy and gratitude. I must make the conscious effort to step away from myself to enjoy what I’m actually seeing rather than lamenting what I’m missing. Spring flashes past so quickly and I can never really hope to truly appreciate it all, but there is much I can relish.

So here’s to spring. Every first flower and every last, to the plants that bring us so much at this time of the year. Here’s to them all, from the common-or-garden right to the dazzling rarities.

Here’s to the unceasing joy of spring, which comes each year regardless of what turmoil there is in the human world.

Share

Every time we venture into the gardens there’s something else. For some of you, in colder areas than the mild South West region of the UK, this is all still to come; you might still be enjoying the last remnants of winter while spring is whizzing by here!

Spring is definitely peak season for what should probably correctly be called geophytes, those plants that grow from bulbs, tubers and other underground storage organs. We gardeners tend to loosely refer to them as ‘bulbs’, largely because following the Raunkiær system of classifying plants is seldom our first priority when we’re thinking about plants, but also because the nice people at the garden centre might well give us a strange look if we ask them where all the geophytes are.

The subject for this week’s Plant Files is a true bulb by any normal definition and goes by the full name of Camassia leichtlinii subspecies suksdorfii Caerulea Group. For ease I will refer to them as Camassia leichtlinii Caerulea Group from here on.

These are the largest of the camassias we see in Britain. I suspect they’re the largest species of the whole genus; it’s probably safe to say that if there was a bigger one it would have been introduces by now.

Camassia leichtlinii itself is native to the North West of the USA and the west of Canada, where it’s generally found in seasonally wet meadows. The tall spikes of flowers must look spectacular in long grass.

Indeed I think they’re much better grown in long grass in gardens. They aren’t the prettiest thing as they die back in summer, not helped of course by their size, and you must be quite careful to plant them with herbaceous plants that use the blank space they leave in the border. Yet in long grass you have the advantage that the grass hides the dying foliage as it grows up. By the time you’re looking to clear away the long grass later in the year the camassias have long been dormant. Some sources say they’ll reach 1.5m, around 5ft, in height; I’ve never seen them reach that sort of height, but they probably do reach around a metre, just over 3ft, in height as a routine. Maybe the taller flowerspikes come when the bulbs reach a larger size.

I’ve found Camassia leichtlinii Caerulea Group to be largely trouble-free. In fact I’ve not knowingly had problems with rodents digging them up, and nothing seems to eat them as they come up and flower. I’ve even been impressed by how weatherproof they are – this is very important in a region where it rains quite a lot in spring! For the non-purist wildflower enthusiast these bulbs add a useful bit of interest early in the season and are then hidden by the later flowering plants.

You can grow the Camassia leichtlinii Caerulea Group in most conditions but I’ve found that they really thrive in heavier and seasonally wetter soils. The smaller camassias, those more akin to our wild bluebells and much better suited to the borders, are a little less keen on being waterlogged in winter.

British gardener Keith Wiley, creator of the garden at Wildside in Devon, has raised a range of different forms of Camassia leichtlinii. Some are darker blues than the Caerulea Group while others are purple or even a blue that touches on being pink. These have been lovingly raised from seeds and as far as I know have not been shared widely.

For the rest of us Camassia leichtlinii Caerulea Group will have to do, although it’s far from a hardship. Spires of electric blue flowers in spring are still very much a treat, and although they can be a bit big for smaller spaces they are absolutely wonderful in the right place.

Camassia leichtlinii Caerulea Group is completely hardy in the UK, USDA hardiness zones 3-8. Seasonal moisture is their friend, especially in late winter into spring. That said, they don’t need to be ‘wet’ as such; the usual soggy UK winter and spring is just fine.

Share

But look at this with a gardener’s eye and tell me what’s wrong with this scene?

It’s clear that this roof has been like this for many years, so the big question for me is how are these plants alive?! Mosses are supposed to need abundant moisture to thrive, yet here we have mosses thriving on whatever they can grab hold of and clearly coping with periods of summer drought. They hold enough water to allow some small flowering plants, my favourite being the lacy-leafed Geranium robertianum, to grow to their proper size. Further along there was a wild thistle in flower last year at about one sixth of its potential size. This whole ecosystem thrives despite seasonal drought and what must be very few nutrients.

This is not a garden. It is a weedy rood that will appeal to a tiny minority of people who see beauty and intrigue in these miniature worlds. It’s not difficult to see how the green roof revolution came about: by understanding how a few weeds grow on a roof like this it’s not a big jump to tweak the species and the environment to make a really brilliant green roof.

A few months ago I went to a talk given by a great guy called Dusty Gedge.

Dusty is regarded as a pioneer of the green roof revolution; he has spearheaded a lot of the industry best practice and his work on promoting green roofs is admired globally. During his talk – one of those talks that you find yourself remembering details from weeks and months later – he talked about the value of lean horticulture. It was quite a moment for me; like quite a few people in the gardening world I’ve been questioning the narrative around yield in gardens, and here in a room full of horticultural professionals was someone else who had come to the same conclusions I had come to.

Dusty went on to tell us about the problems with using organic matter on green roofs. You’ve got some fairly obvious questions around the weight of wet material and how to strengthen the building to support it, but there was also the issue of fire; if you use compost on a green roof and it catches fire it would essentially turn into a ‘peat fire’. Peat fires are difficult to start but once started are very challenging to put out. Once organic matter becomes hydrophobic – essentially impossible to wet – water applied will run between the particles of organic matter rather than saturating them and slowing the spread of the fire.

By using non-organic substrate like clay balls, gravel and sand there is an almost negligible fire risk. But as we all know plants need lots of rich soil, nutrients and water.

Or do they? Gardeners obsess over mulching and feeding their soils to make their gardens ‘healthy’, but in the wide world beyond our garden gates we find that nature is very mean. Soils vary wildly, and the humus-rich alluvial soils gardeners long for is actually pretty rare globally. Gardening culture is obsessed with yield, be it yield of vegetables, yield of growth, or yield of flowers and fruits. We’ve picked up this ideology from agriculture and it’s become ingrained in our collective gardening psyche. Consequently gardening is remarkably heavy on inputs, but does it need to be?

Conventional gardening lore measures the success and health of a garden by its yield. To pass muster your plants must be as big as it’s possible to get them, must have the absolute highest possibly number of flowers, and if ornamental or edible fruits follow then they must be the biggest and most numerous. To step away from this fundamental idea requires bravery, not only to take a horticultural risk in your own garden but to potentially face the wrath of the horticultural intelligentsia. Turning one’s back on convention is a controversial course of action, and even those like Dusty Gedge, John Little and Peter Korn who have made names for themselves by challenging the norms find themselves at the edge of the horticultural world despite being able to prove that their methods work. Gardening is very conservative; it prefers tradition and routine over innovation and change.

Even though plants thrive in their native environment despite comparative hardships, and even though horticultural pioneers are successfully growing an ever-expanding range of plants in non-soil materials ranging from sand and gravel right through to crushed building waste, gardeners are dutifully composting and mulching to ‘improve’ their soil. I’m reminded at this point of my first encounter with non-organic matter growing media back in the early 2000s. There was a representative for a company called Seramis showing off the company’s baked clay granules at a local garden centre. At the time I was into cacti and the guy pointed out that I was growing my cacti in compost while wild cacti grow in very gritty, rocky soil. I bought a bag but never used it; I wasn’t ready to break with convention in those days.

One of the greatest challenges to the idea of lean gardening is that the never-ending cycle of mulching and feeding clearly works; plants grow well so why change? It’s only when you start to look a little deeper that questions arise.

Are there disadvantages to the gluttonous garden? The short answer is yes, but the extent of the disadvantages depends very much on a near-infinite number of variables. Things like soil type and climate are obvious, as is the choice of plants growing in the garden, but other variables like whether the root system became pinched in its pot at the nursery, the clone of the plant and even whether the plant was planted as a young plant or as a specimen are a little harder to quantify. The problem is that to get the garden right from the beginning would require probably a decade of fairly intensive research and analysis before planting, and gardeners are generally reluctant to treat their garden as an ongoing experiment when they spend so much time and money trying to make a garden they enjoy.

Why take a risk when there are tried and tested ways to follow?

The answer this comes back to that rather weighty word ‘sustainability’. The endless cycle of feeding and mulching is costly in terms of time, effort and money. The cut and drop technique, advocated by an increasing number of actual gardeners alongside opinionated designers and social media influencers, is not actually the perfect answer it’s touted as being. Yes there are big advantages to cutting the woody old stems of your herbaceous plants into little twiggy bits: the material feeds natural biological processes of the soil, creates habitat for beetles and large ground fauna, and it also saves a lot of time dragging material from the borders, composting it and then dragging it back. Maybe the compost area of your garden is conveniently situated, but in many gardens it is not. The downside to cut and drop is that it’s very easy to end up with too much material, or too much material of a certain type. The old stems of miscanthus are a good example of this; most gardeners are sensible enough to resort to the mechanical help of a hedge trimmer or even garden shredder with miscanthus, but even a modestly sized plant with a small footprint in the border can yield a lot of material.

You need to be wary when using the cut and drop method, although this seems to have escaped the understanding of all too many of its proponents. Success comes down to a judgement call; too great a depth of material is one thing, but the depth acceptable to border plants depends on the type of material you’re leaving behind and the tolerances of individual species. Some plants will take a light covering of thin material for example, while many don’t want their crowns covered at all. Some don’t tolerate more than the thinnest layer of material over their roots even if their emerging stems are open to the sky. Cutting and dropping material is only part of the process; you must ensure that you only leave an appropriate depth of material behind.

Healthy soil is measured by the number, and diversity, of soil organisms. Yes the idea of yield is a foundation of our understanding of soil health too; the higher the yield of soil organisms the better your soil is. It’s a metric that works well ideologically in the garden but falls flat on its face when you consider plants in their wild habitats. A great many garden plants thrive in meadows and edges of woodlands in the wild, places where competition for resources between plants is often exacerbated by what are by conventional standards ‘poor’ soils. Too many plants thrive in natural habitats where their growing medium stretches the very definition of the word ‘soil’ for gardeners to simply ignore the gap between how plants grow in the wild and how we perceive they must be grown in cultivation.

Few gardeners in the temperate regions have to deal with truly ‘bad’ or ‘unhealthy’ soil. We might have heavy soil or soil that is thin and sandy. This is not going to be an argument for working with your weeds – although there is sense to this – but is instead an argument that we should garden for our conditions, rather than choosing what sort of garden we want and trying to influence millennia of geological, biological and environmental processes to suit our desires. If your soil isn’t how you want it then expect to be adding organic matter in large quantities for a very long time before it will make a meaningful difference.

Many years ago I met a frustrated clematis enthusiast from Southport, up in the North West of England. His garden soil was what’s known as ‘grey dune’, the inland bit of sand dunes where organic matter is just starting to build up but the soil is primarily sand. No matter how much compost, topsoil and farmyard manure he added the ground just absorbed it all, and every clematis he planted shrivelled up and died. What he could grow, however, was the silver-leafed Convolvulus cneorum to a quite frankly rude size. Everyone else struggles with this plant in even poor soils this gardener grew it to 2m or 6ft tall and wide. But couldn’t grow the clematises he loved but could instead grow a plant he pretty much loathed.

There are great advantages to adopting a lean approach to ornamental gardening, and I would argue that most gardeners could probably ease off on the feeding of soils in productive gardening. There’s the time and effort saved by not moving material around and composting. Weeds luxuriate in compost mulches, and by denying them their rich source of organic matter you will find yourself with fewer weeds to deal with. Adding compost to soil is great for plants because it’s a form of organic matter plants, including weeds, can take up easily, but compost is far less beneficial to many of the creatures that live in soil. Plants can be incredibly lazy if they’re looked after too well, but if that care is interrupted then the garden quickly finds itself in peril; during periods of drought it’s seldom the plants that are already used to fending for themselves that suffer.

The question is whether we as gardeners are willing to compromise. Lean gardening has its advantages and disadvantages. As I see it the key disadvantages are that you will need to compromise on flowering and to turn your back on the idea of excessive growth being a sign of good health, and you will need to be at peace with the idea that some plants won’t grow in your garden without intensive intervention. Is there more to gardening though than fighting to keep overfed plants healthy while keeping others on life support simply to be able to enjoy them? The advantage is that your garden plants will grow more as nature intended, and are less susceptible to the pests and problems associated with ‘soft’ plants.

I wonder also if some of our familiar garden plants haven’t been telling us that our traditional ways of gardening aren’t right? In the last few years I’ve started to notice a pattern with ornamental cherries, lilacs and buddlejas, with a few other plants too; the fewer inputs the happier they seem to be. Grow certain plants in well-maintained nutrient-rich conditions and they seem to grow at a prodigious rate but then start to suffer from pathogens or get damaged in bad weather, but where they fend for themselves in less than perfect conditions they seem to thrive.

To make lean gardening make sense we have to look again at what constitutes healthy soil. The current preoccupation with the number and diversity of soil organisms has a neat logic to it, yet at the same time it ignores the success of different ecosystems in nature that are rooted in what would be classed as ‘poor’ soil. That guy in Southport whose garden soil lost organic matter as soon as he applied it would never have met the currently held definition of healthy soil, but some plants still grew well for him. Indeed very few of us will have optimum soils by the current standards, but our plants grow and thrive. It’s a flaw in ecological thinking to assume that the best result is lots of diversity in a small space. Fun as it is to wag fingers and say I’ve got more diversity than you have it only really applies if that diversity is sustainable. If you only reach optimum standards of garden and soil health with constant inputs of organic matter then I would argue that this goes against the principles of sustainability, and that we should be open to the idea that there’s not one single standard or metric for what constitutes a healthy garden.

I’m not saying that you shouldn’t mulch and feed plants – the subject of mulch itself is yet another subject on my increasingly long list of topics to discuss – but there is logic in the idea that maybe it would be prudent to ease back on such practices to encourage our plants to fend for themselves.

The ornamental quinces, belonging to the genus Chaenomeles, certainly fit the bill in many ways. They’re about as tough as you could want a plant to be, largely unpalatable to pests and diseases, and if cared for appropriately they will flower very well

.Where gardeners tend to fall out with the ornamental quinces is the flowering. Some gardeners find shades of orange, red and pink a little too much. Of course that’s perfectly fine, and it’s absolutely the case that positioning the plant appropriately is key to success. The lighter pinks and oranges are perfect against a dark stone wall, while the classic crimson is at its best against a lighter surface.

Some gardeners simply don’t like these colours, which is also completely acceptable. There are white forms which fit the bill in some cases, but sometimes what’s needed is something altogether softer.

Enter the subject of this week’s Plant Files, Chaenomeles ‘Yukigotan’.

It would be hard not to see the appeal of this delightful and elegant form of what has become something of a utility shrub over recent decades. No brashly coloured flowers here; instead elegant rose-like double flowers of creamy white tinged green. These would be charming enough even if the plant was in full leaf, but emerging as they do just before or at the point where the bright green leaves emerge makes for quite the perfect effect.

Later you get the fruits. I’m told that the fruits of several ornamental quinces are rather nice when cooked but have no experience to call on. You’re on your own with that one!

Chaenomeles ‘Yukigotan’ will make a shrub maybe 3m or 10ft tall and wide in time. It’s largely ignored by rabbits and deer – the wire mesh in the image above is to prevent the plant being dug up by rabbits, not eaten – which makes it useful for rural gardens. It’s hardy across the whole of the UK, USDA zones 5-9. Generally it’s happiest in normal garden soil, away from extremes of drought and wet.

The number of pests and diseases has increased. It’s partly down to changing climate patterns, for example species that would have been killed off by cold weather are now surviving warmer winters, and strengthening winds blow spores and insects over greater distances, but international trade and travel also plays their part. Some countries might seem quite draconian with their biosecurity practices but it’s the easiest thing for a pest or disease to travel internationally hidden away in a consignment of something.

We are also becoming far more aware of interloping species thanks to better science and communication, and a good thing too. If we are to enjoy our gardens, and the world around us, we should pay attention to the potential threats that are around. Not to the level of paranoia of course, but just be well-informed.

I’m going to focus this week on one particular pathogen, Camellia Petal Blight, partly because this is very much ‘in season’ here in the UK but also because it provides a conveniently neat and tidy example of how pathogens can work in gardens.

Camellia Petal Blight is caused by a fungus, Ciborinia camelliae, that affects the flowers of camellias. Pathogens that affect only one genus are fairly rare, and pathogens that only affect one physical element or part of one type of plant are really very unusual indeed. Most pathogens target leaves, and many spread through the vascular system of the plant. A depressing number are ultimately fatal, although plants usually put up quite a fight and some keep their diseases under control. Camellia Petal Blight is quite unusual for infecting only the flowers and not the plant’s leaves and vascular system.

It was first identified on camellias in Japan in 1919 and has since spread around the world. It’s fairly new to the UK, but its arrival was always inevitable. The fungus spreads over great distances, its spores carried on the wind. Those land on open flowers, infect them, and when the flowers fall the fungus is deposited into the soil beneath the plant. There it stays, dormant, before producing more fruiting bodies from late February to around the beginning of April, and infecting the next generation of flowers. There are no treatments, organic or synthetic.

And neither will there be. To protect flowers from Camellia Petal Blight would require daily application of a product, maybe even twice daily, as the flowers open. Even if there was some magic cure you cannot hope to be on top of every single flower even on a plant of modest size. Spores in the soil are very challenging to deal with. Effective soil fungicides were withdrawn from sale in the UK many years ago, and should be treated with caution in places where they remain available. Fungi are a vital part of a healthy soil, and there will not be anything that picks off the pathogen and leaves beneficial fungi alone. Damage your soil fungi and there is every chance that what replaces them will be far more harmful.

You may or may not be particularly interested in camellias, and you may or may not consider Camellia Petal Blight to be a problem. However in the discussion around how gardeners might tackle this issue we must look at some sound horticultural principles that will be relevant to all gardeners.

Monoculture is the enemy of effective pest and disease management. Gather large numbers of the same sorts of plants and you will sooner or later attract the pests and diseases of those plants. Doesn’t matter what you grow, you will end up with problems at some point. Spreading plants around spreads the risk. Camellia Petal Blight is able to spread like wildfire across even large camellias because the flowers are so often physically close together; the plant itself creates a sort of floral monoculture, and the fungus jumps from flower to flower, and of course where plants are grown in close proximity the spores can jump from plant to plant. If only we could physically keep the flowers apart...

You could do this in two ways. One would be to disbud the camellia, to thin the buds out so that when the flowers open they are further apart. I’m not a huge fan of this approach, especially on larger plants, because it would be a time consuming job for relatively little gain. There is a good argument that says to do this with smaller camellias, especially those buds nearer the base of the plant. Another more sensible way involves pruning the shrubs themselves.

A knowledgeable gardening friend told me that Japanese gardeners never pass up on an opportunity to prune and train trees and shrubs, creating the interesting shapes and forms that I love to see in my books. Japanese gardens have had Camellia Petal Blight for over a century but have not given up on camellias; I ask whether this is because their camellias contribute more to their gardens than just large green masses of plant when not in flower. European-style gardening seems to favour the ‘big blob’ style, but let’s be honest here and say that camellias are seldom interesting out of flower. If a pathogen is going to wipe out their flowers, the one reason to grow camellias, then that’s not going to help their cause.

Pruning and training would have the added advantage of opening up the structure of the plant, letting air through and providing gaps or ‘firebreaks’ between flowers. Here we touch on a key principle of pest and disease management, the importance of airflow. So many garden plants become susceptible to problems when they have still air around them. Raised humidity levels help fungi spread through foliage, and small insects like scale insects and aphids thrive when they don’t have to cope with dry air and when predators can’t find them among dense stems and leaves. Ventilation isn’t just important for greenhouses, it’s for the whole garden.

With Camellia Petal Blight we have two vectors for infection to consider. Firstly we have the spores that are blown into our gardens by the wind, but we also have the issue of spores emerging from the soil below. In principle we could deal with this a few different ways. Pruning the lower branches of larger camellias – a canopy lift as it’s often called – will provide distance between the soil and the lower branches, and their flowers. Sure airborne spores that can be blown hundreds of miles or more on strong winds will still bridge the gap between the soil surface and the plant, but the further the spores have to travel the less likely they are to reach their destination. If the lowest flowers of the plant are next to the ground then there’s a very good chance they will take a full dose of spores when they’re released.

But what if we put a physical barrier between the potential source of infection and the flowers? In principle a nice mulch, applied before the fungus releases spores from below, would greatly suppress the release of new spores. You might not be able to rid yourself of the fungus itself but you can at least curtail its spread. Cleanliness is key with any plant material – remove infected or potentially infected material to reduce what is called ‘disease pressure’ – so whatever material would need to be removed along with the dropped flowers. We’re back into aggravating jobs that will take time and effort, plus cost if you need to import materials for the job. To mulch under camellias for the few months when spores emerge from the ground would be expensive and require the infected mulch to be removed and disposed of appropriately. I wonder though if certain herbaceous plants could help us.

Spring ephemerals, plants that do their whole growth cycle during a few weeks of spring, are often overlooked by gardeners. Generally speaking we like our plants to grow for as long as possible rather than leaving us with bare soil. There are plants like the woodland cardamines that are utterly fabulous for their short season, and when they die back the year’s floral debris can be raked out without issue. Other alternatives would be plants like the lower comfrey varieties, things like Symphytum ‘Hidcote Blue’, herbaceous plants early enough into leaf that they can suppress the new spores but tough enough to cope with damage caused by clearing away old flowers.

I don’t have any miracle answers for Camellia Petal Blight, but I’m still drawn to the idea that we shouldn’t just give up on a genus of shrubs just because there’s a disease around. Not everyone likes camellias of course, and this is fine; if you have a plant you don’t like in your garden and it shows susceptibility to disease then maybe this is the time when you remove it. The message here is to resist the urge to go removing plants from your garden at the first sign of trouble, and to make informed decisions when choosing new plants. Autumn flowering camellias, for example, are totally unaffected by Petal Blight, while those with long flowering seasons will have a period of susceptibility but with good flowering before and after the fungus’ active period.

Over the years we gardeners have been told that certain plants will become ungrowable in the future due to one problem or another, but we’ve learned to deal with problems as they arise.

The management of Camellia Petal Blight won’t come from a bottle, it will come from good garden management; this is true for so many challenges we face. The key issue is to understand ‘disease pressure’, or the balance between pathogens and potential hosts. If the disease pressure is high – lots of pathogenic organisms in a given area and a few susceptible plants – then the chances of infection are very high. However if disease pressure is low, so fewer pathogenic organisms despite a number of plants to infect, then things are weighted in favour of the plants. By far the easiest way to reduce ‘disease pressure’ is to have fewer of the same type of plant in close proximity.

You may recall that I recently caught a viral cold at a flower show. I’m much better now – thank you to everyone who wished me well – but it was an interesting example of how ‘disease pressure’ works with people. The chances of one person passing on their cold to everyone at the event was statistically fairly slim, but I likely met a few people who were infectious or spent a prolonged amount of time with an infectious person, so the odds of staying healthy were not in my favour.

By reducing ‘disease pressure’ we can reduce the chances of our plants catching unpleasant pests or diseases in the first place, and this relies on wise gardening and good husbandry where we know problems might occur. In the case of Petal Blight the cleaning up of fallen flowers is going be be very beneficial, but in the case of other pathogens it might be a case of clearing up fallen leaves instead.

Ultimately the worst thing gardeners can do is panic and worry, and the second worst thing to do is ignore risk. All too often the information we’re given about a new problem comes with a large dose of sensationalist doom-mongering. We must all take new information seriously but look first and foremost at sensible, logical ways of keeping our gardens healthy. Something as simple as not growing excessive numbers of one plant, an idea almost unnervingly obvious, helps us to avoid or at least minimise most pest and disease problems.

Share Pen And Trowel