Scientific: Ricinus communis
Common: castor bean, palma Cristi, wonder tree
Family: Euphorbiaceae
Origin: Originally from northeastern Africa and the Middle East but has spread to become pan tropical. Also, has naturalized in coastal riparians areas of central California south into northern Baja California.

Pronounciation: Ri-CI-nus com-MU-nis

Hardiness zones
Sunset 13-24
USDA 9-11

Landscape Use: Stunning garden accent or focal shrub or small tree.

Form & Character: Upright, sparsely branched, bold, visually demanding.

Growth Habit: Evergreen, herbaceous or semi-woody, broadleaf perennial large shrub or small tree. In frost free zones and tropical regions, castor bean can grow moderate to rapid to as much as 40-feet tall and 15-feet wide. In Phoenix, castor bean is markedly smaller due to the high heat and potential for frost in winter. Younger stems and leaves are deep reddish in color.

Foliage/texture: Large foliage to 12- to 30-inches long and width, strong palmate veination, 5 to 11 deeply incised lobes per leaf; very coarse texture.

Flowers & fruits: Flowers are generally small, female flowers have conspicuous red stigmas, male flowers have conspicuous yellow anthers; fruit are reddish brown egg-shaped capsules, about an inch long and thickly covered with soft flexible spines. Each capsule contains three seeds that look like fat swollen dog ticks, and are highly poisonous.

Toxicity warning: Castor bean fruit are deadly poisonous! Soviet KGB agents were suspected of killing BBC journalist and communist defector Georgi Markov in the autumn of 1978 as he walked across the London bridge by jabbing him in the calf with the sharp tip of a metal umbrella. The umbrella tip was laced with ricin, the poisonous extract of the castor bean seed.

Seasonal color: Foliage often turns reddish during winter, pinkish red flowers during spring.

Temperature: Heat tolerant, but frost sensitive and killed by freezing temperatures.

Light: Full sun

Soil: Tolerant.

Watering: In desert locations, irrigate regularly especially during summer.

Pruning: None, except to remove old or dead leaves.

Propagation: Seed, quick to germiniation if water soaked for 24 hours or mechanically scarified.

Disease and pests: None

Additional comments: In climates with freezing temperatures, castor bean is grown as an annual. Otherwise in milder climates, it is a mostly large, perennial herb.

There are several named cultivars including:

'Carmencita'- bronzy red leaves and bright red female flowers.

'Impala' - dwarf to 5-feet tall, red leaves that age to purple.

'Sanguineus' - blood red stems and leaves.

'Gibsonii Mirabilis' - dwarf to 4-feet tall, dark red leaves and stems.

'Zanzibarensis' - large and robust with green leaves having white veins.

Biomedical tidbit: Castor oil (ricin removed through processesing) has been an effective home remedy for centuries to soothe sore muscles, reduce inflammation, and as a mild laxative.