Family: Euphorbiaceae
Common Name: Castor Oil Plant, Castor Bean

This single-species genus is grown mainly in its Asian habitat for the oil yielded by the seeds, which is used medicinally and for manufacturing soaps and varnishes. The large, bright green, deeply divided, veined leaves are very decorative, and a number of variously coloured leaf forms are available. Woolly sprays of greenish cream flowers are borne in summer. This frost-tender, evergreen shrub is usually grown as an annual, often included in summer bed-ding schemes, in patio containers, and in sub-tropical borders.

Species

R. communiis grows to around 2 m (6 ft) in cool climates where it is usually treated as an annual, and 5-10 m (16-33 ft) in the tropics. The flowers have no petals, but masses of stamens. Cultivars include 'Carmencita', 'Impala' and 'Red Spire', all of which display rich foliage and stem colour and often heavy fluting of the leaves, and 'Zanzibarensis', which has very large, green leaves, prominently veined in white.

Cultivation

In frost-prone climates, propagate from seed sown in spring and germinated at 21°C (70°F). Plant out when frosts are over. In milder climates, sow in spring where the plants are to grow.

Climate

Zone 9 to tropical.