The genus Stapelia comprises a challenging and rewarding group of about 50 species of clump-forming stem-succulents from southern Africa. The leafless four-angled stems have toothed edges and can be pubescent. Stems grow erect, branching mainly from the base, and develop a reddish color in strong sunlight.
Stapelias have unusual, often large, five-lobed flowers, which may be red, purple, or yellow, often with interesting banded patterns. The surface can be brightly polished or matted with hairs. Most species produce a putrid odor of rotting carrion to attract blowflies as pollinators, which explains their popular name of "Carrion Flowers." Stapelia erectiflora and Stapelia flavopurpurea have sweetly scented flowers.
The genus Stapelia was historically merged with the genus Orbea. However, leach (1975) re-separated Orbea into its own genus.
Growing Conditions and General Care
Several species are relatively easy to grow. Others, often those with slightly hairy stems and the more unusual flowers, are more challenging and require careful watering (with some fertilizer) during the growing season and complete water withdrawal during the winter months.
A minimum winter temperature of 50 °F (10 °C) is acceptable, providing that plants are kept dry. A heated growing bench or incubator may help delicate plants to get through the colder months. However, many species live under shrubs in their habitat and prefer light shade rather than full sun.
A gritty compost is essential, and clay pots are advisable for the more delicate species. Some growers prefer mineral-only compost to minimize the chance of a fungal attack on the roots. A layer of grit on the surface of soil prevents moisture from accumulating around the stems' base.
Keeping Stapelias and their roots free of pests such as mealybugs is the real key to success as fungal attack often occurs due to damage to stems by insects. Watering with a good systemic insecticide such as those based on imidacloprid should help to keep plants healthy.