FlowerBean
Castor Bean
Castor bean is a fast-growing tropical perennial grown as a warm-weather annual in most of North America, reaching 6 to 10 feet tall in a single season. Native to tropical Africa, this plant commands attention with its enormous, glossy, deeply lobed leaves and showy flower and fruit clusters that bloom from June through October. In hardiness zones 9-11, it thrives year-round; elsewhere, sow seeds indoors 6-8 weeks before your last spring frost and transplant after danger passes. It tolerates drought, handles full sun to part shade, and demands minimal maintenance once established, though it grows most vigorously and flowers most prolifically in full sun.
Photo © True Leaf Market
Growing Conditions
USDA Zone
9-11
Sunlight
Full Sun
Water
Moderate
Soil
Well-drained Loam, Tolerates Poor Soil
Growth Stats
120 in
Height
48 in
Width
TypeUpright
Spacing
36
Plant Profile
Sunlight
Full Sun
Water
Moderate
Zones
9-11
Size
120in H x 48in W
Growth
—
Care
Moderate
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Highlights
Castor bean grows with almost alarming speed, shooting up 6 to 10 feet in a single season with huge, palmately lobed leaves that give a tropical feel to any garden. The plant produces showy flower spikes followed by equally ornamental seed capsules, flowering continuously from June through October in warm climates. Its drought tolerance and forgiving nature make it one of the most resilient and fastest-growing plants available, thriving in full sun with moderate water and low maintenance once it takes off.
Common Uses
Castor bean is grown primarily as an ornamental plant for its dramatic foliage and showy flower and fruit displays. The enormous, glossy, deeply lobed leaves create a bold tropical effect in gardens, borders, and containers, while the distinctive flower spikes and seed capsules provide visual interest throughout the warm season. Its rapid growth and height make it particularly valuable for creating quick summer screening or as a statement plant in the back of ornamental gardens.
Growing Timeline
No timeline data available yet for this variety.
Care Instructions
Start Indoors
Sow seeds indoors in pots about 6-8 weeks before your last spring frost date, using soil temperatures of 70-85°F for germination.
Transplant Outdoors
After the last spring frost date has passed and soil has warmed, harden off seedlings by gradually exposing them to outdoor conditions over 7-10 days, then transplant into the garden spacing them 36 inches apart with 48 inches between rows.
Direct Sow
In USDA zones 9-11, sow seed directly in the garden at the last spring frost date.
Pruning
Pinch off seed capsules when small to prevent self-seeding and remove the poisonous seeds from the plant, especially in households with small children. No other pruning is necessary given the plant's upright growth habit.
Growing Calendar
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Companion Planting
Pests & Diseases
Ecology & Traits
Drought Tolerant
Bloom Time
June To October
Tolerances
Drought
Scientific Classification
Ricinus communis
Family
Euphorbiaceae
Genus
Ricinus
Growth Habit
Upright
Native Status
L48 (I)HI (I)PR (I)VI (I)
History & Origin
“Ricinus communis likely originated in tropical Africa, though its true native range remains somewhat mysterious due to centuries of cultivation across warm regions worldwide. The plant has proven so adaptable that it has naturalized throughout North America, escaping from gardens into fields, waste areas, and roadsides, particularly in regions like Missouri where it establishes itself readily. This aggressive naturalization speaks to the plant's remarkable vigor and resilience, qualities that have made it both valued as an ornamental and monitored as a potential invasive species in certain climates.”