In frost-free areas, castor bean is an evergreen herbaceous or semi-woody large shrub or small tree that gets up to 40' tall and 15' wide. In the tropics, it can have a trunk that is woody near the base and up to a foot in diameter. Elsewhere, castor bean plant grows as an annual that can get 4-15' tall in a single growing season. This is a fast growing, colony forming plant with decidedly tropical looking foliage. They tend to grow straight up at first, developing branches only later in the season (and in subsequent years for plants that live that long).
The huge leaves are palmate, with 5-11 deeply incised lobes. They are glossy green to purplish or reddish-green and 12-30" across, with long petioles (leaf stems). The flowers are followed by green to reddish brown egg-shaped capsules, about an inch long, thickly covered with soft flexible spines. Annual. Grows quick like a regular bean. A noble foliage plant, the extracted Castor oil has been used as a medicine for centuries.
► Note: Seeds of this plants are poison. Consider your children and pets.