Ricinus communis, commonly known as castor bean plants, are tall tree-like plants that grown in warm areas year-round or as summer annuals in cooler parts of the world. Their leaves are somewhat star-shaped with 5-9 lobes. The spiky, greenish-red seed pods are an interesting sight on most plants, but the pointy, bright red seed pods of the ‘Impala’ variety are particularly fascinating (the same goes for the scarlet or dark purple tinted leaves). The individual seeds have interesting designs once broken out of their containers (each pod contains 3 seeds, normally). However, the entire plant (especially the seeds) are highly toxic and should not be consumed under any circumstances.
Ricinus communis (Castor Bean, Castor Oil Plant)
Deciduous: no (evergreen in tropical zones)
Hardiness Zones: 9-11
Height: to 3.5 meters tall, rarely larger (in St. Louis area, may grow to be nearly 3 meters tall in one growing season!)
Diameter: to 1.2 meter spread as an annual
Growth Rate: fast (outcompetes many other plants in Central America and parts of northeast Africa)
Age: several years in tropical regions (exact number not stated)
Root System: thick near base, becoming very extensive
Subspecies: ‘Impala’, others
Tolerates: drought (especially once mature)
Problems (major): The plant is poisonous (particularly the seeds) and can cause serious illness if ingested.
Problems (minor): invasive, very frost tender
Poisonous: The entire plant produces Ricin, a compound that inhibits RNA translation by hydrolyzing an Adenine (making transcription fail and altering protein production). Ricin may be concentrated up to 4% in the seeds but is far less in other portions of the plant.
Soil requirements: evenly moist, well-drained loams (medium soils) from a pH of 5.8 to 7.0
Air Requirements: sensitive to lead (Pb) contamination
Watering requirement: dry to moderate (intolerant of prolonged wet soils)
Sun requirements: full sun required
Annual/Biennial/Perennial: frost tender perennial
Flowering structure: spherical, round, yellow/pink/green, small clusters to 3 centimeters in diameter
Flowering frequency: late summer, regardless of size (‘Imapala’ saplings as small as 0.5 meters tall flowered for me)
Fruit: hexagonal/round seed pods with small thorn-like protrusions outside, 3 shiny black or intricately designed seeds per pod
Ricinus communis ‘Impala’ has beautiful scarlet-dark purple leaves with bright red, fuzzy seed pods. These grow quickly where light and weather permits; they are potentially invasive in some areas of Florida, California, central America, and Africa for this reason.
The oil from the seeds is used commercially for various purposes, such as lubricants, varnishes, and plastics. The toxins from the plant (primarily the seeds), known as ricin, is sometimes used as a medium to destroy cancer cells. The poisonous chemicals inside of the plant often kills cells, and this quality is occasionally used to try to destroy cancerous tumors. Some research shows that it possibly could be used to fight AIDS-infected cells to prevent spreading. The oil has been used as a laxative in food poisoning. The taste may be used to induce vomiting. Castor-oil plants have been used externally to treat itches, sores, and to remove dandruff. The seed is sometimes used as a contraceptive in some parts of Africa. The intense poison from the seeds has been rarely used to kill mice. NOTICE: One seed, if consumed, is powerful enough to kill children (typically 12 years old and younger).
A newly germinated seedling, parts of the roots are pink; the cotyledons are somewhat visible
A young castor bean plant, with cotyledons and specialized leaves visible
A close-up of a cotyledon
R. communis ‘Impala’ seeds, the protruding structure to their left is where the primary roots emerges.
These previous images were taken by me and may be used for educational/informational purposes provided that this blog/article is appropriately cited/referenced first.