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

Native to South Africa, most species of zantedeschia are grown as greenhouse plants in temperate zones. The exception is Zantedeschia aethiopica, the calla lily or arum lily, which -if in pots - can be set outside in the summer, or - in a border or at the water's edge - left outside all year. These are exceptionally beautiful plants, with thick glossy leaves and large white flower spathes.

GROWING Pots: set rhizomes 7.5cm/3in deep in 2.5cm/l0in pots of compost in early spring. Water in, and keep moist at 5°C/41°F minimum until growth appears. Increase watering gradually and feed with liquid fertilizer weekly in summer. Move pots outside in mid summer. Bring inside in autumn and repot in fresh soil. Outdoors: as a water plant Z. aethiopica needs 15-30cm/6-12in water. In the open ground, very rich soil is needed. In water or in the border, protect the plants from frost with a laycr of bracken or straw.

PROPAGATION Divide the rhizomes when repotting or lift and divide outdoor plants in autumn. Replant immediately.

VARIETIES `Crowborough', hardier than the species, recommended for outdoor cultivation.

POSSIBLE PROBLEMS Corm rot.