Family: Saxifragaceae

This genus consists of well over 300 species of lovely, dwarf perennials which are found in temperate and alpine areas throughout the world. Many cultivars have been developed and these make attractive additions to cool-climate rock and alpine gardens. Although the genus has been divided into 16 groups to aid identification, there is still some dispute over which species are actually grown.

Many are cultivated in the UK, particularly by rock-garden specialists. The leaves are variable and may be linear or geraniumlike, or often variegated, while some form succulent rosettes. The flower clusters are mainly pink to purple, white, cream or yellow, and are usually borne on spikes above the low, sometimes clump-forming foliage.

Species

S. paniculata, zone 2, from central Europe, forms mats of longish, gray-green leaves, carried in rosettes. The plant flowers in early summer, bearing panicles of cream-white blooms. It grows to a height of about 15 cm (6 in) and will spread to about 30 cm (12 in). There are numerous varieties and cultivars available. Grow in a well-drained, alkaline soil, in full sun.

S. rosacea, zone 6, is one of the mossy saxifrages, forming clumps of bright green leaves of variable shape only 8 cm (3 in) high. The usually white, open flowers are borne in spring. Cultivars provide masses of flowers in a range of red, bright carmine and pink.

S. stolonifera, Aaron's beard, mother of thou-sands, roving sailor or strawberry geranium, zone 8, is a native of Japan. It has geranium-like, olive green leaves, attractively veined in silver, and long spikes of white, spring flowers. Ideal for growing in a hanging basket, it prefers an acid soil and semi-shade. It forms clumps of about 30 cm (12 in) in height. The main feature of the many cultivars is the prettily variegated leaves.

S. umbrosa, zone 7, grows to a height and spread of around 20 cm (8 in), forming rosettes of fleshy leaves. A profusion of tiny, starry, white flowers appears on tall stems in spring. Grow this species in shade with moist soil. Cultivars of this and other species are available. Consult local garden centers and mail order growers for types suited to local conditions.

Cultivation

Requirements vary widely, some species needing shade and moist soil, others requiring full sun and very well drained soil. Some need acid soil, others alkaline conditions. Gardeners wishing to grow saxifrages should consult a specialist book on alpines to ascertain plant needs. Most are propagated by division or offsets in spring.

Climate

There are species suited to various climatic zones.