garden notes 33, ivy, words of warning, pruning clematis, an apology

I’ve mentioned events in the garden before. Like when the snowdrops open. Events which mark a particular moment in the year and often carry emotional associations. For some reason I’ve been more aware of them this year. The last one is taking place now, it’s been showing for a week and will run for another two, and it’s one which is easily overlooked, it’s the flowering of the ivy.

Builders hate ivy. So do architects and surveyors and insurance companies. And not only them, of course. Builders say that it destroys the pointing in brick walls. but gardeners, who know better, say that it only damages pointing that is already loose, and that it helps to keep walls dry. When ivy grows up a tree or a building the stems hold on by means of a thick brushlike growth of tiny rootlets which are known as adventitious roots. They don’t grow into the brickwork, they just cling to the surface. If when ivy is cut and pulled away the pointing is loose and crumbly it will come away with the ivy. So when you get somebody to repoint the wall some of the expensive work of raking out the joints will already have been done for you.

Ivy can be managed in fruitful ways. If you allow the vigorous young shoots to grow over a window in the summer it will cut out harsh sunlight during a drought. Then you cut it back in the autumn. Or you could leave it for a bit of protection from winter storms and cut it back in the spring. Of course if the ivy gets to the top of the wall and starts to send long new shoots under the slates and block the gutter, that can be very annoying, especially if you live in a tall house.

Ivy growing up a house will not flower well, especially if it’s regularly cut. It flowers when it’s got nowhere to go. Up a tree it will grow and grow and when it comes out into the light at the top of the tree it will develop flowering shoots, and these shoots have a different habit. Unlike the usual long, single, pliant shoots the inflorescence is carried on branching, woody, stiff stems. Wisteria behaves in a similar way, so that it will rarely flower well on a high wall if it is never allowed to get to the top of it, but will perform beautifully on a fence that might be only six feet high. (There’s a superb one on the railings of St Paul’s cathedral.) My garden has thick, confused boundaries dominated by ivy, some wild and native, some garden varieties. The neglect of the gardens on either side has been benign. I’ve been lucky to avoid conflict with neighbours wanting to cut everything back. The fences underneath disappeared years ago. When ivy develops it will stand alone and make a good hedge. So although it’s thick I do cut it back regularly. But in the summer, when I see the flowering shoots develop, I leave it uncut on top. And sometimes I dig and take an axe to its roots in the winter, to stop them from colonising too much of the garden. And I need to watch out for the prostrate shoots which can creep out several feet unseen, rooting as they go. So it’s quite a lot of work.

The flowers are a last source of nectar for enterprising insects. This is what makes it a proper event, I suppose. And then there are berries. They’re not particularly good to eat, it seems, for the birds leave them till quite late in the winter, but this makes them a valuable resource in a hard year.

The photos of bees at the ivy flowers were taken yesterday, October 10.


2. Words of warning. Hard frost after heavy rain is a killing combination for tender plants in pots. The wet induces rot and freezing turns the whole rootball into a block of ice. The worst thing you can do now is leave pots sitting in saucers overflowing with rain water. It’s common when autumn brings a falling away of vigilance, the retreat indoors. And those nice cheap porous terracotta pots split, sometimes interestingly like shattered shale. Pelargoniums and salvias which at least in London and the south west are borderline hardy can be protected from further rain – and snow – with sheets of glass or tucked into dryish corners up against the house.

3. Clematis tangutica on September 13

The pruning of clematis can be confusing, especially if you don’t know what kind you have, and most people don’t. In a nut shell, there are three kinds. If it has big flowers quite early in the year – May – and doesn’t grow like bindweed but has restrained proportions, don’t prune it hard. In the winter just tidy it up, cut away feeble and dying shoots. If, like C. jackmannii which we’ve seen recently, it spreads and climbs at speed and flowers later, beginning in July, then cut it back hard. the books say to about two feet, but you can leave it longer than that, especially if it’s growing up through something big enough to be a match for it, like my dense and prickly Rosa Stanwell Perpetual. (One thing I like R. S.P. for is that it was noticed growing in a hedgerow in Stanwell, near where Heathrow Airport is now, I imagine. It evidently has R. spinosissima in its genes because its prickles are as dense as the wires on a wire brush, and its stems crowd so thickly together that robins can invisibly nest in it. Its leaves are dainty and healthy. It flowers in a rush in May-June, and thereafter always has a sprinkling of flowers until the winter. I cut out some of the old stems in the winter, shorten some of the longest new growth, and train it by ramming large forked branches into it to pin it back to the fence, what’s left of it.
The third kind of clematis are the species, wild and unrefined, including one of my favourites, C. tangutica, with its nodding yellow bells, and the ubiquitous spring flowering C. montana and its varieties. you don’t need to do anything to these, unless they get too big, apart from cutting out some of the dead shoots. The difficulty with this is that it can be quite hard to tell if a shoot is dead or alive, if it’s growing in the middle of a tangle and you can’t see its tip. sometimes I’ve scraped a wee bit of the bark off to see if it’s fresh and living underneath or brown and dead. But if you prune a big C. montana after it’s flowered, in spring, it will put on so much new growth that any mistakes you make will become insignificant. Cematis tangutica seems to flower from the old wood quite early in the year, in June-July, and then again, more so, in September, from the current season’s growth. And it has beautiful seed heads all through the winter which look tousled and ruined after rain, but dry out and fluff up fresh and blond again.
A volunteer at Meanwhile Gardens in Paddington once cut a big C. armandii, that’s the one with big white flowers in winter, right to the ground. True, it didn’t flower well the following winter but it grew eight feet or more that summer and was well set up for the future. And remember, don’t give up, believe in resurrection! (and compost.) And watch out for slugs and snails early in the year. As with many plants, once they get going, they’re fine, it’s those first tender shoots which attract hungry slugs.

Resurrection does seem to happen with clematis: a common form of wilt can kill the entire plant above the ground, but the roots can recover, and a year later it may return.

4. Sorry about my IT complaints in the last post. I found a way. I’ve now added the photo of the contender for worst example of municipal pruning which I could only refer to before.

here it is again, why not:

next time, nerines again!

This entry was posted in gardens. Bookmark the permalink.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s