Plant Assessment Form

Ricinus communis

Common Names: castor bean

Evaluated on: 12/22/04

List committee review date: 16/05/2005

Re-evaluation date:


Elizabeth Brusati, project manager
California Invasive Plant Council
1442A Walnut St. #462, Berkeley, CA 94709

List commitee members

Carla Bossard
Matt Brooks
Joe DiTomaso
Peter Warner
Jake Sigg
Cynthia Roye

General Comments

No general comments for this species

Table 2. Criteria, Section, and Overall Scores

Overall Score? Limited
Alert Status? No Alert
Documentation? 3 out of 5
Score Documentation
1.1 ?Impact on abiotic ecosystem processes U Reviewed Scientific Publication
Four-part score UBCD Total Score
1.2 ?Impact on plant community B. Moderate Other Published Material
1.3 ?Impact on higher trophic levels C. Minor Other Published Material
1.4 ?Impact on genetic integrity D. None Other Published Material
2.1 ?Role of anthropogenic and natural disturbance in establishment B. Moderate Other Published Material
Total Points
15 Total Score B
2.2 ?Local rate of spread with no management A. Increases rapidly Observational
2.3 ?Recent trend in total area infested within state B. Increasing less rapidly Observational
2.4 ?Innate reproductive potential
(see Worksheet A)
A. High Other Published Material
2.5 ?Potential for human-caused dispersal B. Moderate Other Published Material
2.6 ? Potential for natural long-distance dispersal B. Occasional Other Published Material
2.7 ?Other regions invaded C. Already invaded Other Published Material
3.1 ?Ecological amplitude/Range
(see Worksheet C)
A. Widespread Other Published Material
Total Score B
3.2 ?Distribution/Peak frequency
(see Worksheet C)
D. Very low Observational

Table 3. Documentation

Scores are explained in the "Criteria for Categorizing Invasive Non-Native Plants that Threaten Wildlands".

Section 1: Impact
Question 1.1 Impact on abiotic ecosystem processes? U Reviewed Scientific Publication
Identify ecosystem processes impacted:

No information available.

Sources of information:

Question 1.2 Impact on plant community composition,
structure, and interactions?
B Other Published Material
Identify type of impact or alteration:

Grows fast and forms dense monoculture that displaces native vegetation in riparian zones (1,2). However, these monocultures are generally restricted to railroad tracks or other disturbed areas and native species can coexist with Ricinus (3).

Sources of information:

1. Burrascano, C. 2000. 269-273. in Bossard, C. M., J. M. Randall, and M. C. Hoshovsky (ed.) Invasive plants of California's wildlands. University of California Press. Berkeley, CA.
2. Perala, C., D.A. Hoover, and E.A. Parra-Szijj. 1993. Control of exotic plants in an herbaceous understory. CalEPPC News 1(3): 4-6.
3. Matt Brooks, Research Botanist, USGS, Henderson, NV. Personal communication

Question 1.3 Impact on higher trophic levels? C Other Published Material
Identify type of impact or alteration:

All parts of plants are toxic (1). Probably displaces some riparian species because it replaces native vegetation with much denser cover, but I found no information on this.

Sources of information:

1. Fuller and McClintock. 1986. Poisonous plants of California.

Question 1.4 Impact on genetic integrity? D Other Published Material

None No related native species

Sources of information:

Burrascano 2000

Section 2: Invasiveness
Question 2.1 Role of anthropogenic and natural disturbance
in establishment?
A Observational
Describe role of disturbance:

Escapes from cropland and landscaping. Common in abandoned fields, along roads and railroad tracks, and in drainage ditches. Seeds can germinate quickly after fire.

Sources of information:

Burrascano 2000

Question 2.2 Local rate of spread with no management? A Observational
Describe rate of spread:

In southern California, capable of doubling in riparian areas within less than five years.

Sources of information:

E-mail from Cindy Burrascano, California Native Plant Society, 2/15/05

Question 2.3 Recent trend in total area infested within state? B Observational
Describe trend:

In California, R. communis has naturalized below 1,000 feet elevation in the southern San Joaquin Valley, along the central and south coast, in the San Francisco Bay Area, in Trinity County, and in coastal southern California (1). Solstice Canyon Park, Santa Monica Mountains Recreation Area (2). Controlled in Laguna Hills to reduce fire hazards (3). Listed as a species that causes problems in wildlands in the Inland Empire (4). Listed for eradication in Santa Barbara County by the Santa Botanic Garden (5). Controlled repeatedly on Catalina Island (6). Spreading in riparian areas in Torrey Pines State Beach. Most open space districts in San Diego have to remove it if they have riparian areas. Spreading at Tijuana Estuary and Santa Monica mountains. Not as bad as tamarisk because frost knocks it back temporarily (7).

Sources of information:

1. Burrascano 2000
2. Perala et al. 1993
3. Ames, J. No date. City of Laguna Hills weed abatement supplemental guidelines.
California State Parks. 2000. Urban edge effects and their relationship with the natural environment. Pp. 1-30. California State Parks Inland Empire District.
5. Santa Barbara Botanic Garden. No date. Worst invasive plants in Santa Barbara County: exotic species to eradicate if found on your property.
6. Knapp, J.J. 2003. Personal observation of Catalina Conservancy conservation efforts..
7. E-mail from Cindy Burrascano, California Native Plant Society, 2/15/05

Question 2.4 Innate reproductive potential? A Other Published Material
Describe key reproductive characteristics:

Plants are monoecious. Spreads by seed and is capable of resprouting from root crown when cut. Seeds are spiny capsules (1), and are large (2). Seed pods dehisce when ripe and spread seeds near parent plant (1). Does not spread by root fragments (1). Annual or perennial, depending on whether it's killed by a cold winter. Seeds need long frost-free period to develop.

Sources of information:

1. Burrascano 2000
2. Smith, D. T. 1972. Survival and Emergence of Volunteer Castor Seed in Soil. Agronomy Journal 64(6): 799-801

Question 2.5 Potential for human-caused dispersal? B Other Published Material
Identify dispersal mechanisms:

Cultivated for oil and as an ornamental. Found in Cal-IPC 2004 nursery survey. Seeds can be spread by road maintenance machinery or by transport of soil. Not often sold in the nursery industry today.

Sources of information:

Burrascano 2000

Question 2.6 Potential for natural long-distance dispersal? B Other Published Material
Identify dispersal mechanisms:

Moving water (1) and mammals (2).

Sources of information:

Question 2.7 Other regions invaded? C Other Published Material
Identify other regions:

Cultivated and naturalized in Southern U.S., midwest, and Oregon (1). Invades riparian areas in Namibia (2). Listed as invasive in Florida and Wyoming (3).

Sources of information:

1. Burrascano 2000
2. Boyer, D. C. and H. J. Boyer 1989. The Status of Alien Invasive Plants in the Major Rivers of the Namib Naukluft Park Namibia. Madoqua 16(1): 51-58.
3. USDA PLANTS database. Accessed 12/22/04

Section 3: Distribution
Question 3.1 Ecological amplitude/Range? A Other Published Material

Frequently found in riparian areas, especially along southern and central coast. Distribution limited by intolerance of cold temperatures (1). Locally abundant in riparian corridors and canyons near the urban/wildland interface in southern California and in some areas is invading uplands from roadsides (1).

Sources of information:

1. Burrascano 2000
2. E-mail from Bill Neil, 2/22/05

Question 3.2 Distribution/Peak frequency? D Observational
Describe distribution:

Not common in wildland habitats. More common in southern California coastal riparian areas than elsewhere in the state.

Sources of information:

DiTomaso, observational.

Worksheet A - Innate reproductive potential

Reaches reproductive maturity in 2 years or less Yes
Dense infestations produce >1,000 viable seed per square meter No
Populations of this species produce seeds every year. Yes
Seed production sustained over 3 or more months within a population annually Yes
Seeds remain viable in soil for three or more years Yes
Viable seed produced with both self-pollination and cross-pollination No
Has quickly spreading vegetative structures (rhizomes, roots, etc.) that may root at nodes No
Fragments easily and fragments can become established elsewhere Yes
Resprouts readily when cut, grazed, or burned Yes
Total points: 8
Total unknowns: 0
Total score: A?

Related traits:

Worksheet B - Arizona Ecological Types is not included here

Worksheet C - California Ecological Types

(sensu Holland 1986)
Major Ecological Types Minor Ecological Types Code?
Marine Systemsmarine systems
Freshwater and Estuarine lakes, ponds, reservoirs
Aquatic Systemsrivers, streams, canals
Scrub and Chaparralcoastal bluff scrubD, < 5%
coastal scrub
Sonoran desert scrub
Mojavean desert scrub (incl. Joshua tree woodland)
Great Basin scrub
chenopod scrub
montane dwarf scrub
Upper Sonoran subshrub scrub
Grasslands, Vernal Pools, Meadows, and other Herb Communitiescoastal prairieD, < 5%
valley and foothill grassland
Great Basin grassland
vernal pool
meadow and seep
alkali playa
pebble plain
Bog and Marshbog and fen
marsh and swamp
Riparian and Bottomland habitatriparian forest
riparian woodlandD, < 5%
riparian scrub (incl.desert washes)D, < 5%
Woodlandcismontane woodland
piñon and juniper woodland
Sonoran thorn woodland
Forestbroadleaved upland forest
North Coast coniferous forest
closed cone coniferous forest
lower montane coniferous forest
upper montane coniferous forest
subalpine coniferous forest
Alpine Habitatsalpine boulder and rock field
alpine dwarf scrub
Amplitude (breadth): B
Distribution (highest score): D

Infested Jepson Regions

Click here for a map of Jepson regions

  • Cascade Range
  • Central West
  • Great Valley
  • Northwest
  • Sierra Nevada
  • Southwest
  • Sierra Nevada East
  • Desert Province
  • Mojave Desert
  • Sonoran Desert