Quick Guide: summer, hardy, full sun, height: 7.5cm/3in, width: 60cm/24in

Although the daisy-like white flowers are charming, cerastiums are chiefly valued for their dense, silvery foliage. The common name, snow-in-summer, is very apt, as these perennial plants form a thick white carpet over the ground. Some species are invasive, others nothing but weeds. Take care to obtain those recommended.

GROWING Plant in spring or early autumn in poor, well drained soil in a sunny position. A south-facing bank is ideal. Protect the foliage from damp in winter with a pane of glass.

PROPAGATION Divide established plants in summer and replant immediately.

SPECIES Cerastium tomentosum (above)is pretty but invasive; the form C. t. columnae is neater and can be contained; C. alpinum can be recommended at 10em/4in high, spreading only 23cm/9in and flowering all summer. A good late-flowerinl-I species is C. pyrenaicum, with tufted green leaves.

POSSIBLE PROBLEMS Generally trouble-free.