Rhododendron problems

One of the gardens I look after is a woodland garden of about two thirds of an acre, where every plant seems to be about 20 feet tall. It's lovely - but I do seem to find myself doing a lot of pruning!

They've developed a terrible problem with rhododendron bud blast - a fungal disease thought to be spread by a leaf hopper. The leaf hopper is harmless by itself, but lays its eggs by making tiny slits in the buds of rhododendron flowers - which then becomes an entry point for the bud blast fungus.

You can tell bud blast because the buds turn black and look bristly. It's becoming a very common problem - last time I was at RHS Wisley a lot of their rhododendron bushes were affected. Goodness knows how they keep on top of it there.

You can spray against the leaf hoppers, but I've always thought that seemed a bit harsh (and very unfriendly to the environment). The usual treatment is to pick off the affected buds and burn them, but try doing that when the rhododendron bush is twice as high as you are. And you always miss a few, in any case.

I think we'll just have to keep at it and get as many as we can, and hope the problem doesn't do for the rhododendrons altogether. After all, there's not much point in keeping these rather sombre shrubs in your garden if they aren't even going to flower.

Plant of the month - March

Narcissus "Tete-a-Tete"


It just had to be daffodils - the garden is really coming alive now, with plenty of spring flowers nodding in the breeze, but daffodils just steal the show every March. This is one of my favourites: I'm not a fan of the larger types, except for cutting, and of the miniatures Tete-a-Tete has the purest flower form and colour that I know. If you cut a single bloom and take a close look, you'll see how utterly perfect it is. It may be everywhere these days - but there's a reason for that, and it puts a smile on your face every time.

Plant-buying season again...

I have the extreme good fortune to live not very far from RHS Wisley, which is about as close to a centre of horticultural excellence as you can get. The gardens are wonderful at pretty much any time of year, and it's one of the places I go as a reference for how things ought to be done.

They also have the best garden centre for miles there, and though the plants are a bit on the expensive side, they are without exception beautifully grown and the highest-quality plants it's possible to buy. I've never had a single one I've got from there keel over on me, which is more than you can say for a lot of nurseries.

The garden centre runs an excellent ordering service, allowing you to source obscure plants simply by putting your name down for it at the information desk. I did exactly that for the last few plants on my list for my Dixter tribute border, and they've come up trumps - a postcard dropped through the letterbox yesterday telling me they've now got Spiraea japonica "Gold Mound".

The young leaves on this compact shrub are more of a pale yellow than its parent, S. japonica "Gold Flame", in which they're a kind of butterscotch orange. I dislike "Gold Flame" for the revolting clash of colours which happens when it flowers - candy pink and butterscotch orange have to be the most horrible combination ever. But pink on greeny-yellow might look a lot nicer, and the habit of both is a really lovely compact fountain, which combined with the prettiness of their new spring foliage makes them very good garden shrubs, so I'm happy to give it another try.

You learn something new every day

It's amazing - no matter how long you've been gardening, there's always something new to try.

I've been sowing seeds for my cutting garden (a new development this year), herbaceous garden and of course the tropical bit around the pond courtesy of Ventnor Botanic Gardens.

The tropical seeds were the ones I thought would be trickiest, but in fact they've turned out to be pretty straightforward and in many cases don't even need a propagator. It's good old lupin seeds that have got me trying something new.

I've always heard about sanding seeds and often wondered "what's all that about then?". Certainly I've never bothered with it - sweet peas, the usual candidates, always germinate fine for me without any special treatment at all. But for once I read the seed packet on my Lupin "Morello Red" seeds for the cutting garden, and was a bit surprised to find they needed sanding and soaking before you sow them. Perhaps that's why I've never had much success germinating lupins before - I always thought it was the slugs...

Anyway, so I've taken an old emery board and gently sanded one end of each seed (ooh so fiddly... ) and they're now soaking in tepid water for a couple of hours before I sow them. Let's see if it makes a difference.

Taming winter jasmine

I have one client who really loves winter jasmine (Jasminum nudiflorum) - she has it across one entire wall of her very beautiful 17th-century house. She was wondering why it was getting leggy and hardly flowering at all, so she asked me to sort it out.

Well, once I got up close and personal, it was pretty obvious what had been going on. In an attempt to keep this sometimes unruly shrub back against the wall, she had been trimming it much like a hedge all summer. Result - all the sun-ripened growth which should have borne this winter's flowers had been chopped right off. The plant had been trying to replace its lost flowers by producing more and more shoots, which were then also trimmed, resulting in a plant that looked like it had bottle-brushes on the end of its stems! The long, whippy woody stems hadn't been encouraged to produce the usual green flower-bearing shoots from lower down, so they had also remained bare and the whole thing was in a truly sorry state.

Fortunately it was reasonably easy to put right. I trimmed back the older long whippy shoots to cut off the bottle-brushes, then took out a few of them to reduce the density. The few green shoots which remained I've cut back to a couple of buds from the main stems - which you should do annually at this time of year, after flowering, to keep them productive.

With a bit of luck, next year the plants will be producing new strong growth from the base, and the dormant buds on the woody framework stems should spring into life. My poor client got a (gentle!) lecture from me about leaving well alone during the year and tying in wayward shoots rather than chopping them off - and I left her, and her plants, a lot happier.

It's such a shame that so often plants which perform beautifully are prevented from doing so by sheer ignorance about how they do what they do (often by the most well-meaning of people). Mind you, it's also what makes my job so satisfying - I can fix a lot of these kinds of problems relatively easily, and am treated like a magician when miraculously the plant does what it wanted to do all along!

Covering everything in ****

After spending a month pruning roses, I'm now spending a month shovelling sh**!

I'm a very big fan of mulching, especially lately since we've been having such terrible droughts in the summer. I'm certain that my deep mulch last spring saved most of my plants from certain death in the 30 degree temperatures and hosepipe bans last July. I didn't water my garden once - not even the big herbaceous border - and it all pulled through bar one Helianthus (ah... my poor Lemon Queen... still sad about that one).

Mulching does such a lot of good. It holds the winter's rain into the soil. It suppresses weeds for months: I won't have to weed any of these gardens for a month or so now. And most importantly, if you use well-rotted manure (you can tell it's well-rotted if it doesn't smell - and if it's well-rotted, you shouldn't get weed seeds) then it feeds your soil all year long. I generally put down another feed - usually pelleted chicken manure - underneath the mulch to give plants a feed right away, since it takes a month to get the mulch moving down into the soil and the chicken manure feeds them in the meantime. And that's it - low maintenance gardening that's good for plants!