Common name: Caster Bean, Castor Oil Plant
Family: Euphorbiaceae (Spurge)
Height x width: 5-10' x 5-10' (to 40' high in native habitats)
Growth habit: upright, branched
Growth rate: rapid
Foliage: alternate, large to 3' across but generally 1' across, palmately 5-11 lobed, lobes ovate to lanceolate and serrate; many colors but generally variation on red
Flowers: monoecious, not significant, no petals, in axillary panicles; fruit are about one inch, smooth or spiny
Hardiness: USDA zone 9
Soil: well drained, fertile
Light: sun
Pests and Problems: spider mites when young indoors; spindly and smaller leaves, more flowers, on poor soil and less fertility, and shade
Landscape habit, uses: specimen for size and foliage color, back of borders;
Other interest: foliage contact may cause irritation, all parts especially the seeds are poisonous if ingested; seeds are used for an oil, in turn used medicinally and in soap, paints and varnishes; genus from Latin ricinus for tick, which seeds resemble; native from N.E. Africa to Western Asia; naturalized on wastelands such as along roads and stony slopes in warm climates
Other culture: usually too large for containers and easily and quickly grown from seed so generally not overwintered; may need staking if on exposed and windy sites; very frost sensitive
Propagation: seeds sown directly, or shortly before planting out in the north
Species: only this one in the genus
Cultivars: there are only a few cultivars, these being the main
ones, and it is often found as simply the species
| Cultivar | foliage | other |
| 'Carmencita' | maroon | rose red seed pods, RHS award |
| 'Carmencita Pink' | maroon | pink seed pods |
| 'Gibsonii' | dark red | compact 4-5' |
| 'Impala' | dark red | compact 4-5', young growth carmine |
| 'Sanguineus' | blood red | stems red also |
| 'Zanzibarensis' | green, white veins | tall 6-10' |
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