Quick Guide: spring, hardy, full sun, height: 30cm/12in, width: 45cm/18in

Thanks to the brightness of its profuse yellow flowers, Alyssum saxatile (above) has an impact out of proportion to its diminutive size. This popular perennial, commonly known as gold dust, is a shrubby plant with narrow, pointed, grey-green leaves. It carries its tin v blooms into the first weeks of summer. For a continuation of colour, plant with A. argenteunt, which blooms all summer.

GROWING Plant between autumn and spring on light, free draining soil. Over-rich soils are unsuitable. Cut back hard after flowering for sturdy growth and to keep the shape neat.

PROPAGATION Take 5cm/2in cuttings in early summer and insert in a peat/sand mixture in a cold frame until rooted. Pot up individually and grow on in the frame. Plant out the following spring.

VARIETIES `Citrinum', sharp yellow; `Compactum', neat, half the height of the species; 'Plenum' syn. `Flore-Pleno', double golden-yellow flowers; 'Dudley Neville', dull gold.

POSSIBLE PROBLEMS Slugs may eat young plants; downy mildew on leaves.