These little beauties, also known as the houseleek, are a must for any rock garden or scree bed, their pretty rosettes creating soft and subtle evergreen interest, especially when dusted with winter frost.

They are also great for growing in winter pots to create an impressive display in foliage shades of green, red and purple. There are all sorts - some are covered in hairs, others are shiny. One of the best known, the cobwebbed houseleek, S. arachnoideum, is wonderful, but try others like Commander Hay', a purplish-red showstopper.

Houseleeks do flower - their fat 12in (30cm) tall stems pushing through the mature rosettes.

To enjoy success they need to be planted preferably in full sun and dry, gritty soil. One thing they hate is excessive moisture and you may have to give them shelter in consistently wet weather to stop the leaves from rotting.