COUNTRY & GARDEN: In praise of prickly thickets

Ornamental brambles beautify a winter garden. However, it's vital that you exercise control.
It is possible, if you are a gardener, to convince yourself that you like the winter. I certainly have. The lawn may be shaggy, the borders sodden and brown, the trees bare and exposed but, nonetheless, I can find plenty of cheering compensations. The catkins on the hazels are lengthening, the snowdrops have nosed above ground, the hellebores are about to unfurl, Viburnum x bodnantense is scenting the air deliciously, the scarlet twigs of Acer davidii gleam in the sun, and the stems of Rubus cockburnianus are at their most intensely white.

Mention the word "ornamental bramble", which this is, and most sensible people blench. The reputation of some species of Rubus for invasiveness is perfectly well- deserved, and all of them exhibit a marked degree of vim and vigour. They are, with only a few exceptions, extremely prickly and they have the capacity to root at their shoot tips, so they are natural makers of thickets. If there is one thing we gardeners find difficult to cope with, it is a prickly thicket. So, as the saying goes, you don't have to be mad to plant them, but it helps.

In fairness, even the most tidy gardener would have to admit that there are a number of "ornamental" Rubus (as opposed to fruiting ones like blackberry, tayberry, loganberry, Japanese wineberry or raspberry) which have lovely flowers. "Benenden" springs immediately to mind. Others, like "Betty Ashburner", have a prostrate habit and so make good groundcover in inhospitable soils and situations, although Rubus tricolor can act like an over-excited, show-off child at a party who doesn't know when to stop. A few, notably Rubus cockburnianus, R biflorus and R thibetanus, have the most lovely stems in winter.

The one I grow is Rubus cockburnianus, which I insist on pronouncing "coburnianus", like the port-wine shippers, because it sounds better, and is almost certainly correct, although I probably earn a reputation for pretentiousness in the process. This deciduous shrub originates in the plantsman's paradise of western Szechuan in China, and was introduced by the great English plant-hunter, E H Wilson, in 1907.

Its growth is like that of a raspberry, in as much as it has biennial stems: they grow one year, and produce flowers the next. These stems arch in an attractive way and can be as much as 8ft long.

And what whiteness! The shoots are always white, where the bloom has not been knocked off them, but, at this time of year, without the leaves to mask them, and with the added spur of lower temperatures, they look as if they had been whitewashed by a master decorator, who has achieved the finest, most even, finish. This whiteness overlays deep purple so that, from a distance and on a grey winter day, the stems look ghostly mauve. If you cut them for Christmas decoration, there is no need to reach for the silver spray-paint, although you will have to mind the prickles.

This shrub has interesting, diamond-shaped leaflets, green above, silver below, which yellow before falling in autumn. The purple flowers are insignificant.

This species is supposed to bear black fruits but my shrubs don't. There is a relative called Rubus biflorus, with larger, white flowers, yellow fruit and a more erect habit (so less likely to have shoots that can touch the ground and root). It came from the Himalayas in the early- 19th century, and was for many years the white-stemmed species most widely grown.

However, it was R cockburnianus which gained the RHS's Award of Garden Merit, and so is more widely available in nurseries these days. Some swear by Rubus thibetanus, especially the variety called "Silver Fern", whose stems are a more bluish-white, with ferny leaves which are silvery above as well as below. This is another one of E H Wilson's introductions.

The trick to living happily with these ornamental brambles is to prune them as if they were autumn-fruiting raspberries, by cutting (with gloves, if you value your skin) the old canes close to the base in late winter or early spring, and thereby making space for the new ones growing up. You sacrifice flowers and fruit this way, but that is a small matter; for since the colour is best on very young canes and, moreover, abrasion of one stem on another tends to remove the waxy bloom, this method ensures the whitest stems in winter.

If you are growing this shrub in a restricted space, it makes sense in summer to snip back any shoots that look as if they might arch over and touch the ground, in order to avoid any danger of thicket-making.

Alternatively, if you have a wild and woolly place in the garden, as I have, where you are happy to let them go, you need do nothing at all. Except take pleasure in them on winter days.