Castor-oil Plant Ricinus communis
Other Common Name(s):
- Phonetic Spelling
- RISS-ih-nuss kom-YOO-niss
- This plant has high severity poison characteristics.
- See below
- Description
-
Castor Bean is an exotic ornamental, semi-woody, fast-growing, large shrub or small tree that is extremely toxic to humans. It can be fatal if only a few seeds are ingested and also causes contact dermatitis when the foliage is handled. It is an herbaceous perennial in winter hardy zones 9 to 11. In colder climates, it is a warm weather annual that readily reseeds itself. The Castor Bean has large, palmately lobed leaves, spiking yellowish-greenish flowers, and spiny seed capsules. It is a member of the Euphorbiaceae or spurge family.
This plant is native to tropical east Africa, but it has naturalized and weedy in many tropical and subtropical areas around the world including the United States. It is usually found along riverbeds, railroads, roadsides, fields, pastures, or other disturbed areas. Castor bean is a noxious weed in southern and central California. The plant is classified as Category II invasive species in the State of Florida.
The genus name, Ricinus, is the Latin word for "tick." This name was given since the seeds resemble a species of European tick. The epithet, communis, means common.
Plant in full sun in rich moist soils. Fertilize regularly for the best growth. Pruning may be necessary to shape the plant. Plants will have low drought tolerance until well established. This shrub is not wind resistant and is easily blown over. Staking may be required. It produces a large number of seeds and readily reseeds itself.
Every part of the plant is poisonous if ingested. The castor bean contains a highly poisonous substance known as ricin that when inhaled or ingested can be lethal to humans and animals. As a preventative measure, the seed capsules may be pinched off when they are small to remove the poisonous seeds from the plant. Handling the foliage may cause severe contact dermatitis Wear gloves and other protective equipment to avoid allergic skin reactions.
Do not plant this in areas where children or pets play due to its toxicity. In the appropriate area, the beautiful and bold foliage adds color and texture to the landscape. Consider this plant as a specimen, container plant, or informal hedge. It is important to remember that this plant grows very fast, and seeds germinate regularly. Plant with purpose and maintain the area to prevent invasiveness. Perhaps better yet, consider a native alternative such as the American Beautyberry, Yaupon Holly, or Fragrant Sumac.
Seasons of Interest:
Bloom: Summer and Fall Foliage: Spring, Summer, and Fall Fruits: Fall
Quick ID Hints:
- annual or herbaceous perennial shrub or small tree, usually up to 6 to 10 feet tall and 2 to 4 feet wide
- stems are red to green or purple
- leaves are glossy, green, star-shaped with 5 to 11 points, serrated margins, and measure 6 to 30 inches wide
- non-petaled yellowish-green flowers appear on spikes measuring up to 18 inches long on the top of the stem
- fruit capsule is red, green, or purple, round, covered in dense spines
- seeds are mottled, smooth, and resemble an engorged dog tick
Insects, Diseases, and Other Plant Problems: The castor bean has no serious insects or disease problems. Spider mites occasionally attack drought-stressed plants.
VIDEO created by Andy Pulte for “Landscape Plant Identification, Taxonomy, and Morphology” a plant identification course offered by the Department of Plant Sciences, University of Tennessee.
- Profile Video:
- See this plant in the following landscape:
- Cultivars / Varieties:
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- 'Carmencita Bright Red'
Dark bronze-red leaves, bright red flowers, and scarlet seed pods - 'Carmencita Pink'
Pinkish-red stems and seed pods - 'Carmencita Rose'
Bluish-green leaves and peach colored seed pods - 'Gibsonii'
Dark red tinged leaves and pink seed pods, grows 4 to 5 feet tall - 'Red Spire'
Red stems, bronze leaves, red seed pods - 'Ricinus'
- 'Sanguineus'
Blood red stems and leaves
- 'Carmencita Bright Red'
- 'Carmencita Bright Red', 'Carmencita Pink', 'Carmencita Rose', 'Gibsonii', 'Red Spire', 'Ricinus', 'Sanguineus'
- Tags:
- Cultivars / Varieties:
-
- 'Carmencita Bright Red'
Dark bronze-red leaves, bright red flowers, and scarlet seed pods - 'Carmencita Pink'
Pinkish-red stems and seed pods - 'Carmencita Rose'
Bluish-green leaves and peach colored seed pods - 'Gibsonii'
Dark red tinged leaves and pink seed pods, grows 4 to 5 feet tall - 'Red Spire'
Red stems, bronze leaves, red seed pods - 'Ricinus'
- 'Sanguineus'
Blood red stems and leaves
- 'Carmencita Bright Red'
- 'Carmencita Bright Red', 'Carmencita Pink', 'Carmencita Rose', 'Gibsonii', 'Red Spire', 'Ricinus', 'Sanguineus'
- Tags:
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-
Attributes:
- Genus:
- Ricinus
- Species:
- communis
- Family:
- Euphorbiaceae
- Uses (Ethnobotany):
- Castor oil is a non-toxic vegetable oil that is extracted from the seeds of this plant. It is used in fabrics, paints, varnishes, ink, crayons, dyes, and ointments. Castor oil is used as a laxative. It has also been used topically to treat ringworm and warts.
- Life Cycle:
- Annual
- Perennial
- Woody
- Recommended Propagation Strategy:
- Seed
- Country Or Region Of Origin:
- Northeastern Africa to the Middle East
- Distribution:
- Naturalized in tropical and subtropical areas around the world including Australia, Mexico, New Zealand, South America, and the United States. Introduced in AL, AZ, AR, CA, CT, DC, DE, FL, GA, HI, IL, KY, LA, MA, MI, MS, MO, NC, NH, NY, OH, PA, TN, TX, and VA.
- Play Value:
- Colorful
- Textural
- Dimensions:
- Height: 6 ft. 0 in. - 10 ft. 0 in.
- Width: 2 ft. 0 in. - 4 ft. 0 in.
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Whole Plant Traits:
- Plant Type:
- Annual
- Herbaceous Perennial
- Poisonous
- Shrub
- Tree
- Woody Plant Leaf Characteristics:
- Broadleaf Evergreen
- Habit/Form:
- Dense
- Erect
- Multi-stemmed
- Growth Rate:
- Rapid
- Maintenance:
- Low
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Cultural Conditions:
- Light:
- Full sun (6 or more hours of direct sunlight a day)
- Soil Texture:
- Loam (Silt)
- Sand
- Soil pH:
- Acid (<6.0)
- Alkaline (>8.0)
- Neutral (6.0-8.0)
- Soil Drainage:
- Good Drainage
- Moist
- Occasionally Dry
- Available Space To Plant:
- 3 feet-6 feet
- 6-feet-12 feet
- USDA Plant Hardiness Zone:
- 9a, 9b, 10a, 10b, 11a, 11b
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Fruit:
- Fruit Color:
- Brown/Copper
- Green
- Purple/Lavender
- Red/Burgundy
- Fruit Value To Gardener:
- Showy
- Fruit Type:
- Capsule
- Fruit Length:
- < 1 inch
- Fruit Width:
- < 1 inch
- Fruit Description:
- The fruits are small, round, red, green, or purple capsules that are covered with dense spines. The capsule turns brown as it matures. They measure 0.5 to 1-inch in diameter and contain three seeds. The seeds are smooth, shiny, and mottled black, gray, brown, yellow-brown, and maroon and white. The seeds resemble a dog tick.
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Flowers:
- Flower Color:
- Gold/Yellow
- Green
- Flower Inflorescence:
- Panicle
- Spike
- Flower Value To Gardener:
- Showy
- Flower Bloom Time:
- Fall
- Summer
- Flower Shape:
- Cup
- Flower Description:
- The flowers are yellowish-green and without petals and appear in tall spikes up to 18 inches long. There are male and female flowers on the same spike. They are pediculate with a 5-parted calyx with many branching stems. The male flowers have cream or yellow stamens. Each female flower has a red stigma and is borne on the tips of the spikes. They bloom from August to November.
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Leaves:
- Woody Plant Leaf Characteristics:
- Broadleaf Evergreen
- Leaf Color:
- Green
- Purple/Lavender
- Leaf Feel:
- Glossy
- Leaf Type:
- Compound (Pinnately , Bipinnately, Palmately)
- Simple
- Leaf Arrangement:
- Alternate
- Leaf Shape:
- Palmatifid
- Peltate
- Leaf Margin:
- Serrate
- Hairs Present:
- No
- Leaf Width:
- > 6 inches
- Leaf Description:
- Leaves are large, alternate, simple, palmately lobed, and glossy green. They have 5 to 11 pointed lobes. The margins are toothed, and the leaf measures can be from 6 to 30 inches wide. They resemble a star.
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Bark:
- Bark Description:
- The trunk is semi-woody in warm climates and can grow to 1 foot in diameter. In cooler climates, the plant remains herbaceous and is slower growing.
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Stem:
- Stem Color:
- Green
- Purple/Lavender
- Red/Burgundy
- Stem Is Aromatic:
- No
- Stem Description:
- The stems are red to green or purple, erect, and branched.
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Landscape:
- Landscape Location:
- Container
- Design Feature:
- Specimen
- Resistance To Challenges:
- Deer
- Drought
- Problems:
- Poisonous to Humans
- Problem for Cats
- Problem for Children
- Problem for Dogs
- Problem for Horses
- Weedy
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Poisonous to Humans:
- Poison Severity:
- High
- Poison Symptoms:
- The seeds can the toxin ricin. If it is ingested or inhaled can be lethal to humans and animals. Immediate or delayed nausea, vomiting, abdominal pain, bloody diarrhea, weakness, colic, depression, loss of appetite, trembling, sweating, loss of coordination, difficulty breathing, sweating, progressive central nervous system depression and fever, convulsions, coma; may be fatal; severe allergic reaction in certain individuals following skin contact with broken seeds. May also be fatal to livestock and pets.
- Poison Toxic Principle:
- Ricin, a phytotoxalbumin, plus ricinine, an alkaloid
- Causes Contact Dermatitis:
- Yes
- Poison Part:
- Flowers
- Leaves
- Sap/Juice
- Seeds