Pruning may feel like murder, but do it well and you'll have happier plants

Pruning is a bit like sculpting. Well, it’s as close as most of us will ever get to the Rodin experience anyway. You need to think about the shape that you are releasing from the mass of material in front of you. It’s not just a matter of hacking away growth that happens to be tripping you up on the garden path. When you are pruning you have to keep in your head a very clear idea of each shrub’s natural form and habit. If you don’t do that, then everything ends up looking the same, humps of barbered greenery, none of it allowed to express an opinion.

Tidiness can be a fault as well as a virtue in a garden. Tidy gardeners get nervous about shrubs getting “out of control” as they put it. But shrubs aren’t delinquent teenagers. They can be taught quite easily how to behave. The teaching should not show though. And if you understand why you are intervening, you’ll get much better results than if you flail around in panic-driven exterminator mode. Pruning is not the same as cutting back. The one just gives you space. The other does that too, but it also enhances performance.

All of us who garden have been watching with interest to see how this fabulous cold winter has affected our plants. We’ve got slap-happy about hardiness. Over the past few years, things that we ought not to be able to grow have flourished. Now some of them are looking rather dead. But I wouldn’t be in any hurry to prune plants that have been cut back by sub-zero temperatures. They may sprout again. So don’t “tidy up” these poor, wind-chilled hostages to fortune. They may yet surprise us. Concentrate your effort on plants that will repay the attention by flowering better than they would if you did nothing. Clematis, jasmine, buddleia, caryopteris, roses, all need pruning now.

I am not, by nature, a tough pruner and have to be feeling particularly irritable to do a decent job on roses. A good, prolonged bout of irritability rarely comes to order at the right time of year.

However, with the image of an intractable traffic warden firmly in mind, I shot out this week between the storms and did a hatchet job on the apricot-coloured ‘Compassion’ rose mixed up with the wisteria on the front of the house. It’s a rose we inherited when we came here and though it flowers well (and repeats through the summer), its habit is stiff and upright.

You can’t fight that, so pruning has to take account of it. Growths can be shortened, upright stems prised apart slightly and tied firmly to vine eyes banged into the wall. More pliable roses can be treated differently, the stems bent over in loose arcs against the wall. Bending roses over like this makes them flower more profusely, the flower buds breaking from the top surface of the stems, which trained like this, are tenser than they would otherwise be.

Vigorous shrub roses can be treated in the same way, if you need room. Often, the advice is not to prune old-fashioned roses such as bourbons and damasks, but much depends on how and where they are growing. In our old garden I grew ‘Ispahan’, a damask rose from the Middle East, “the best of all the once-flowering old garden roses” says Charles Quest-Ritson in his invaluable Encyclopaedia of Roses (Dorling Kindersley, £25). It’s gorgeously scented and has huge, floppy heads of flower, bright icing-sugar pink. I’d thought of it as a reasonably manageable shrub rose, two metres high and wide, but in the clay soil of our rectory garden, it evidently had |its feet in a midden of formidable potency and got to double that size.

Many of the old shrub roses can discreetly be kept within bounds if you corset them with a couple of strong semicircular iron hoops on long legs. ‘Ispahan’ was way beyond this treatment and gradually over a couple of years, each February I rejuvenated the bush by cutting out a couple of the oldest stems (those with the darkest wood) altogether. It hugely improved the look of the thing but also made it flower better. The shrubs around it had more elbow room too. The same treatment would suit other old roses, such as the white Noisette ‘Boule de Neige’ and the pink Bourbon ‘Mme Isaac Pereire’ if they are getting above themselves. It is far better to remove some of the old wood entirely than give the whole shrub an army haircut.

Late-flowering clematis also respond to tough pruning now. It’s not always easy, for the old stems may already be sprouting thick, juicy new growths. It makes you feel like a murderer. I mutter all those

questionable phrases you hear in childhood. “It’ll be good for you in the long run”, “You have to be cruel to be kind”. |Late clematises, though, flower on new growth and this grows much more vigorously on a pruned plant than an unpruned one. It’s worth doing.

Make the cuts about 45cms above the ground, slicing just above a likely pair of buds. If, as will be the case with a well-established clematis, you have five or six stems to deal with, splay them out and tie them in over a wide span, so that as they begin to grow, they will not tangle with each other. For a while, you will remember to keep up with the tying in, but then the whole vigorous mass charges away over whatever support you have given it. This is what it is supposed to do. Enjoy it. Don’t worry about it being “out of control”. Next February, you will be slicing it down close to the ground again.

You do not need to be so vicious with |the mid-season clematis, those, such as ‘Mrs Cholmondeley’, that start flowering with a great burst in May and June but |drift on towards a second flush in August and September. A minor irritation will |do perfectly well for these as they need not so much pruning as thinning. Cut out all the dead growth above the last plump bud or growing shoot. If no more pressing |tasks are at hand, fan out the growing stems over their support. To do this you will need to cut all the tendrils that cling to each other so tenaciously, making the top half of the plant as impenetrable as a back-combed hair-do.

The very broad rule of thumb for shrubs that flower on new wood (like the Viticella clematis) is that they are best pruned just as they finish flowering. But pruning has the effect of stimulating new growth; on late- flowering shrubs that would make them vulnerable to winter weather. Pruning of all late-summer performers which flower on new growth, such as the butterfly bush Buddleja davidii, is therefore best left until now. Buddleia grows at a prodigious rate, so you do not need to be tender with it. Using heavy-duty loppers if necessary, cut back all the previous season’s growth to within 5-8cm of the old wood. Nothing dire will happen to the buddleia if you do not prune, but flowers may well be less showy than those on an unpruned specimen.

Caryopteris is another late-summer shrub that will need attention in the next few weeks. It is a low-growing plant that in August and September bears clusters of soft blue flowers among the pointed grey-green leaves. Cut out entirely any weak, straggly growths and prune the main framework of the shrub hard back, cutting just above young, healthy buds.

Jasmine, now at the end of its season, is often subjected to the haircut treatment. Bushes alongside front doors seem especially prone, all the new growth reduced to a series of stubby green twigs, laid over a thick, tangled bird’s nest of old, barren brown stems. Its natural habit, though lanky, is rather more elegant than this and it is best to arrange it so that the new green growths can cascade down for their full length.

With jasmine, the best way to achieve this is to cut out some old buff-coloured stems entirely each year. With these you will also lose some good new green growths springing from the old but they will quickly be replaced by new shoots breaking at or near the base of the plant. Tie these in closely to the wall or support. As they grow, you can then allow the side growths breaking from the ribs that you have fanned out to fall like a curtain in front of the old stems.

Clematis to be hard pruned now

‘Comtesse de Bouchaud’, C. durandii, ‘Ernest Markham’, ‘Gipsy Queen’, ‘Gravetye Beauty’, ‘Huldine’, ‘Jackmanii Superba’, ‘Lady Betty Balfour’, ‘Star of India’, ‘Ville de Lyon’, and all the late flowering C. viticella varieties such as ‘Abundance’, ‘Alba Luxurians’, ‘Etoile Violette’, ‘Royal Velours’ and their kind

Clematis that needs light pruning now

‘Barbara Jackman’, ‘Beauty of Worcester’, ‘Bees Jubilee’, ‘Daniel Deronda’, ‘Elsa Spath’, ‘Henryi’, ‘Lady Northcliffe’, ‘Marcel Moser’, ‘Marie Boisselot’, ‘Mrs Cholmondeley’, ‘Nelly Moser’ (below), ‘Niobe’, ‘Perle d’Azur’, ‘The President’, ‘Vyvyan Pennell’, ‘Lasurstern’