What Is a Caster Plant?

Castor bean plants are part of the Euphorbiaceae family.

Castor bean plants, or Ricinus communis, are small evergreen trees or large shrubs native to Africa and the Middle East. They are useful as rapidly growing screens or ornamental specimen plants.

Identification

Castor bean plants grow as tall as 40 feet with a 15-foot spread depending upon the climate. They grow considerably taller in frost-free areas than in cooler regions. They have long reddish leaf stems and green, reddish-green or purple leaves with between five and 11 distinct lobes. Female plants produce greenish-yellow blossoms with red stigmas, or pollen-receiving parts, followed by red or brown seed capsules that each contain three attractively mottled brown, gray and white seeds.

Considerations

Castor bean plants are available in several cultivars, such as Impala, which grows between 4 and 5 feet tall and produces reddish purple leaves, and Gibsonii Mirabilis, a 4-foot-tall variety with dark red leaves. Castor bean plants grow as evergreens in USDA Hardiness Zones 10 and 11, but enthusiasts cultivate them as annuals as far north as zone 7, according to FloridaData.com.

Warning

Castor beans contain ricin, a deadly poison. According to Cornell University, a single castor bean seed can kill a child if it is chewed and swallowed. The symptoms of poisoning include diarrhea, nausea, vomiting, trembling and weakness, followed by seizures, coma and death. Castor bean plants have escaped from cultivation and are listed as nuisance weeds in California and Florida.

References

• Floridata: Ricinus Communis
• Cornell University: Ricinus Communis (Castor Bean)
• North Carolina State University: Ricinus Communis