Gardening: Make time to tend the roses

Forget Wimbledon. You must act now to provoke another crop of blooms.

One of the more infuriating features of keen gardeners is the way that, even when the garden appears to be absolutely fine, with plants flowering their heads off and the borders a positive riot of colour, they manage to dream up some, usually arduous, task to do.

Even if you like gardening, it can still be rather annoying. So, all those of you who had earmarked this afternoon for sitting in a darkened room shouting: "Come on, Steffi," prepare to be infuriated.

For this is a critical moment in the year for roses. You can ignore it, and the skies will not fall in on you but, if you want the so-called "repeat-flowerers" to develop another good flush of blooms before the autumn, then you have to be prepared to help them out now.

Many roses flower only once, and no amount of coaxing will persuade them to do otherwise. They are a mixed bag, but include ramblers, some climbers like `Constance Spry', and many of the old garden roses: that is, the gallicas, albas, centifolias, mosses and damasks, together with species roses like Rosa rubiginosa and R. moyesii. On these, there is little point in spending a great deal of time removing the dead heads (unless they are slow to shed them, as ramblers can be) or in feeding them, come to that. (In the case of Rosa moyesii and the single-flowered forms of Rosa rugosa, you will, in any event, want to leave the seedheads to develop into attractive autumn hips.)

It is all the rest - the large-flowered and cluster-flowered bush roses (what we used to call hybrid teas and floribundas), Bourbons, hybrid perpetuals, Chinas, Portlands, polyanthas, a lot of modern climbers and, of course, the modern shrub roses - which benefit from a little trouble taken with them now. Removing the dead and dying flower heads of these roses panics them into making new flowerbuds as soon as possible, in order to try to set seed before the winter, even though in the case of those with double flowers this is a vain aspiration.

This deadheading can be done using secateurs, sharp scissors or even finger and thumb to snap off the stem an inch or two below the head, where the abscission layer may have already started to form.

There is a positive disadvantage in cutting the whole flower stem off, as used to be advised: the flower buds will take longer to form and, in any case, the rose needs all the healthy leaves that it can get for photosynthesis. Even little leaves on spindly twigs play their part in manufacturing food for the plant. It makes sense then to give the plants an energy boost; this is done by scattering a small handful of a quick-acting proprietary rose fertiliser at the base of each rose, and scuffling it lightly with a hoe, taking care not to disturb the roots which lie close to the soil surface. If that soil is still covered in clods of manure, the fertiliser is best watered in.

Rose fertilisers are high in potash which helps flower formation and colour, but they also contain other nutrients such as magnesium and iron which help prevent the leaves from yellowing. This is a task that must be done before the end of July.

If your roses have suffered bad fungal attack, particularly from blackspot, which has been rampant this year, it might be worthwhile spraying the roses, once deadheaded, with a foliar feed of diluted liquid seaweed. This is an organic fertiliser which has some action against fungal diseases and gives the plant an almost immediate fillip because it is taken in through pores in the leaves rather than the roots.

A spot of deadheading and feeding now will make a noticeable difference later on, and can be done quickly. Unless you have dozens of rose bushes, there is every chance you will be finished before the tennis even begins. And if you get out into the garden quickly, I won't have time to think up another job which urgently requires your attention.