Synadenium grantii or African Milk Bush is a succulent shrub or small tree native to East Central Africa. In nature, the plants will reach up to 12 feet (over 3.5 m) in height with an equal spread. The pale green obolanceolate, slightly toothed leaves reach 6 inches (15 cm) long by 2.25 inches (5.7 cm) wide with a short stout petiole approximately 5/16 of an inch (8 mm) long. Leaves are crowded at the tips of the fleshy green branches, which gives rise to a light grey bark. They are of easy culture and are hardy in USDA zones 9-11. The milky sap is very corrosive and can cause contact dermatitis. All plants parts are considered very poisonous. This one should not be grown around small children or animals that like to eat plants.
Blooming: Our plants in the greenhouse bloom during the winter months. The red cyathia are borne in axillary and terminal cymes.
Culture: Synadenium grantii need full sun to light shade with a very well drained soil mix. In the greenhouse, we use a soil mix consisting of 1 part loam to 2 parts sand or perlite with small gravel added to ensure good drainage. Plants are well watered and allowed to dry thoroughly before watering again. We fertilize the plants only once during the year with a balanced fertilizer. The size of the plants is easily controlled by container size. Our plants at 30 years old are about 4 feet (1.25 m) tall in 5 gallon containers. The most important thing about growing these plants is be very careful not to over water them and be very careful to avoid the wounded surfaces when repotting or trimming up unwanted growth because of the corrosive milky sap.
Propagation: Synadenium grantii are propagated from cutting and from seed. When taking cuttings, the fresh cuts should be dipped in charcoal dust to stop the leaking of milky sap and should be struck in sand to root.
Synadenium grantii was featured as Plant of the Week January 27-February 2, 2006.
Guide to Past Plants-of-the-Week:
Cal's Plant of the Week was provided as a service by the University of Oklahoma Department of Microbiology & Plant Biology and specifically the late Cal Lemke, who used to be OU's botany greenhouse grower and an avid gardener at home as well. If the above links don't work, then try the overview site. You may also like to look at the thumbnail index. ©1998-2017 All rights reserved.