Quick Guide: summer, hardy, full sun, height:30cm/12in, width: 60cm/24in

There are several species of helianthemum available, but it is H. nummulnriurn which has earned the name rock rose. This perennial forms dense mounds of small green or grey leaves and bears numerous yellow saucer-shaped flowers 2.5cm/1in across in early summer. The petals are papery, like those of poppies. H. alpestre is a more compact species, H. apennium rather larger.

GROWING Plant in autumn or spring in light, well-drained soil. The rock rose should be cut right back after flowering to keep it neat; all species respond to trimming by flowering a second time in autumn.

PROPAGATION Take 2.5cm/1in cuttings of non-flowering side shoots in mid summer. Place in pots of a peat/sand mixture in a cold frame until rooted. Pot up individually in potting compost and overwinter in the frame. Pinch out the growing tips. Plant out in spring.

VARIETIES H. numznulariaam: `Ben Heckla', copper; `Ben Afflick', orange and buff; `Wisley Pink' (above), rose-pink; `Cerise Queen', rose-red; `The Bride', white; `Beech Park Scarlet', red. H. apenninum: `Roseum', rose red. H. alpestre: `Serpyllifolium', very low growing at 5-7.5cm/2-3in.

POSSIBLE PROBLEMS in hot conditions powde may occur.