: Gardening - plant of the week: potentilla.

Byline: Peter Surridge

THERE are some 500 species of potentilla, including herbaceous perennials, annuals and biennials, but one is more widely grown in gardens than all the others put together.

It is a shrub, Potentilla fruticosa with saucer-shaped flowers produced from spring to autumn and often with silvery leaves. It is hardy, long-flowering and compact enough for small gardens. Most grow to about 1 metre tall and spread to 1.5 metres (3ft x 5ft).

Numerous varieties have been bred from this single species. Their flowers range from white through cream and yellow to pink and red, all with a central boss of golden stamens. Some of the most stunning blooms are found on Red Ace, bright bronze-red; Katherine Dykes, rich yellow; Primrose Beauty, cream with a yellow centre; Daydawn, delicate pink; Princess, richer pink fading to white but with glorious, prominent stamens; Gibson's Scarlet, with brilliant, large blooms; and Sunset, dark orange.

For an even more compact variety, choose Beesii, also known as Nana Argentea, a lovely shrub with silver, silky foliage and golden flowers, reaching 60cm x 1.2 metres (2ft x 4ft).

A few varieties, such as dazzling white Abbotswood, smother themselves in a flush of flowers in May - or April in many places during this fabulous spring - then produce blooms sporadically through the summer into autumn. Others produce a less fulsome display in spring but have a gentle presence in the garden as they stud themselves with successional flowers through to October.

To add to the plant's merit, Potentilla fruticosa and its varieties need virtually no maintenance. Its shape eliminates the need for pruning, and pests and diseases seem to give it a wide berth.

For planting, select a position that is sunny or lightly shaded and soil which drains well but is not too fertile. That will induce lush foliage at the expense of flowers.

When newly-planted, like any shrub, it should be watered generously during dry spells for the first year. After that, if grown in poor soil it will appreciate a handful of fish, blood and bonemeal scattered around the root area in autumn.

The many potentillas are nicknamed cinquefoil from the five-lobed leaves of many species.

One of the herbaceous perennials, Potentilla erecta - oddly named because it sprawls across the ground - is valued in herbal medicine for its high tannin content. Properly prepared extracts from the roots are used to staunch bleeding, reduce inflammation and aid healing.

This is a familiar wild plant throughout Europe, including Britain, on grassy lane verges and heaths, with yellow flowers and the common name of tormentil.

The name potentilla comes from Latin potens, meaning potent or powerful and referring to this and other strong medicinal plants of the same genus.

The largest National Collection of Potentilla fruticosa, 120 varieties, is held at Webbs of Wychbold garden centre in Worcestershire (01527-860000).

The National Collection of herbaceous potentillas, 72 species and 53 varieties, is held by Mr and Mrs D. Goodchild at Ponteland, Northumberland, open by appointment on 01661-823145.

CAPTION(S):

LONGFLOWERING: Bright yellow Potentilla fruticosa