Although not truly black, such dark-colored foliage is highly sought after for its novelty. Because castor bean produces seeds that are poisonous, castor bean plants should not be grown in yards where children play.
According to Karen Platt in Black Magic and Purple Passion (page 193), the following varieties of castor bean plants exhibit dark foliage:
- Ricinus communis 'Carmencita'
- Ricinus communis 'Gibsonii'
- Ricinus communis 'Impala'
- Ricinus communis 'Red Spire'
For more, see how castor bean plants can be used in organic pest control.