Description
This small statured tree comes from northeastern Africa and the Middle East. It is non-native to Florida and considered a category II invasive species by the Florida Exotic Pest Plant Council because it is abundant throughout Florida but has not yet displaced native plant communities. This fast-growing plant is found throughout tropical and subtropical climates on disturbed sites such as edges of roads, old fields, and rocky slopes. Castor bean grows best in full sun and can reach heights of up to 40 feet where frost is not present. In colder climates where temperatures drop below freezing, castor bean functions like an annual plant and only reaches heights of 15 feet. Leaves are simple and alternate and can grow very large; from 15 to 30 inches wide. The green to reddish leaves are palmate with 5 to 11 lobes per leaf and jagged margins or edges. In warmer climates, the semi-woody trunk can reach a foot in diameter, whereas in colder climates the plant remains herbaceous and exhibits slower growing habits. Flowers appear in summer and fall on tall spikes up to 18 inches long that grow out of the top of the stems. Male and female flowers appear on the same spike, with the yellow male flowers pollinating the red female flowers. The fruit is a ½- to 1-inch diameter, spiny capsule that turns from yellow to blue-green and then to brown as it matures. Each capsule houses three small, poisonous seeds that resemble dog ticks.
FOR 244/FR306: Ricinus communis, Castor Bean
Florida Exotic Pest Plant Council Invasive Plant Lists
FLEPPC compiles invasive species lists that are revised every two years. Professional botanists and others perform exhaustive studies to determine invasive exotic plants that should be placed on the lists. Invasive exotic plants are termed Category I invasives when they are altering native plant communities by displacing native species, changing community structures or ecological functions, or hybridizing with natives. This definition does not rely on the economic severity or geographic range of the problem, but on the documented ecological damage caused. Category II invasive exotics have increased in abundance or frequency but have not yet altered Florida plant communities to the extent shown by Category I species. These species may become Category I if ecological damage is demonstrated.
Florida Exotic Pest Plant Council Invasive Plant Lists