Oncoba routledgei

Oncoba routledgei

Oncoba routledgei is a shrub or small tree native to Tropical Africa with dark green crenate leaves that are up to 5 inches (13 cm) long by half as wide. They have small spines that are ¾ to 1 inch (2-2.5 cm) long. In nature they will reach approximately 20 feet (~6.5 m) in height, but in containers their size is easily controlled with selective pruning and keeping the root volume small. They are hardy in USDA zone 10.

Blooming Time: In the greenhouse, the solitary, white flowers appear in spring. Flowers are up to 2 inches (5 cm) across and are mildly fragrant.

Culture: Oncoba routledgei need full sun to partial shade with a rich well-drained soil mix. In the greenhouse, we grow ours under 25% shade all year long. We use a soil mix consisting of 2 parts peat moss to 2 parts loam to 1 part sand or perlite. To this mix, we add 14-14-14 osmocote slow release fertilizer at a rate of 2 tbs (5 ml) per gallon (3.7 L) of pot size. During the growing season the plants are kept moist for optimum growth and fertilized with a balanced fertilizer on a weekly basis. During the winter months, the temperatures are dropped to 50° F (10° C) and water is restricted to about once a week or enough to keep the leaves from dropping.

Propagation: Oncoba routledgei are propagated by cutting or by seed in spring. Cutting are slow to root, so patience is needed. Seeds germinate in 21-30 days at 72° F (22° C).

Oncoba routledgei was featured as Plant of the Week May 16-22, 2003.

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