Quick Guide: summer, hardy, full sun, height: 10cm/4in, width: 60cm/24in

Sometimes listed as Lithospermum, the genus Lithodora belongs to the same family as forget-me-nots, and, like them, bears bright blue star-shaped flowers. The flowers of L. diffusa (above) bloom all summer, emerging from a mat of dark green foliage that makes invaluable ground cover for the rock garden.

GROWING Plant in spring in light soil to which peat or leafmould has been added. This species will not tolerate lime.

PROPAGATION In the summer take soft green cuttings 4-6.5cm /1 1/2 -2 1/2in long with a heel, and insert in a peat/sand mixture in a shaded frame until rooted. Water regularly. Pot up individually, overwinter in the frame and plant out the following spring.

VARIETIES `Grace Ward', clear blue; `Heavenly Blue' (rarely available), profuse, deep blue flowers.

POSSIBLE PROBLEMS Generally trouble-free.