Ricinus communis
Ricinus communis
Castor bean
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Description
Ricinus communis, the castor bean plant, is a dramatic, fast-growing ornamental with huge palmate leaves in green, bronze, or burgundy and spiky seed pods. It thrives in heat and sun, creating a bold, tropical backdrop in a single season. Note: all parts—especially the seeds—are highly toxic if ingested.
Common Names
Castor beanCastor oil plantPalma ChristiHiguerilla
Context
nativeRegion
Northeast Africa (likely the Ethiopian region) and widely naturalized across tropical and subtropical regions worldwide.
usdaZones
Perennial in 10–12; grown as a fast annual in 2–9.
companionPlants
Canna, Dahlia, Banana (Musa), Sunflower (Helianthus), Elephant Ear (Colocasia), Tithonia
culturalUses
Source of castor oil for industrial, cosmetic, and medicinal applications (from processed seeds); ornamental landscaping; traditional uses in various cultures. Note: raw seeds are poisonous and not for consumption.
Care
Care Requirements
LightFull sun (6–8+ hours). Tolerates light shade but foliage is best in strong sun.
WateringModerate. Keep evenly moist while establishing; drought-tolerant once rooted. Avoid waterlogging.
SoilFertile, well-drained soil; loam or sandy loam preferred. pH slightly acidic to neutral. Avoid compacted, soggy sites.
FertilizerFeed with a balanced or nitrogen-leaning fertilizer every 4–6 weeks during active growth, or amend with compost at planting.
HumidityAdaptable; average outdoor humidity is fine.
TemperatureLoves heat. Grow as an annual where frost occurs; perennial in frost-free zones. Protect from temps below 50°F (10°C).
Growth & Life Cycle
HabitUpright, shrub-like or small tree; bold, tropical foliage.
Mature SizeCommonly 6–15 ft tall and 4–10 ft wide in one season; larger in frost-free climates.
Growth RateVery fast growth.
BloomingSummer to early fall; upright racemes with inconspicuous flowers and colorful, spiny seed capsules.
DormancyFrost kills top growth in cool climates (grown as annual). Evergreen/tender perennial in frost-free areas.
Propagation
MethodsSeed
DifficultyEasy from seed (handle with extreme caution; seeds are poisonous).
Best SeasonSpring after last frost; sow indoors 4–6 weeks prior or direct sow in warm soil (70–85°F/21–29°C).
Maintenance & Notes
PruningMinimal. Pinch young tips to encourage branching. Remove spent flower spikes/seed pods to prevent self-seeding and reduce toxicity risk. Stake in windy sites if needed.
RepottingIf container-grown, pot up quickly as plants grow; use deep pots for the taproot. Start seeds in biodegradable pots to reduce transplant shock.
Pests & DiseasesGenerally tough. Possible issues: spider mites, whiteflies, aphids; root rot in poorly drained soil; occasional leaf scorch from wind/drought stress.
ToxicityExtremely toxic—especially seeds (ricin, ricinine). Ingestion can be fatal to humans and animals; sap may irritate skin. Keep away from children, pets, and livestock.
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