Euphorbia heterochroma aka African Cathedral Plant

Euphorbia heterochroma is a shrub in the spurge family, Euphorbiaceae. It is evergreen and succulent, with thick stems that look cactus-like. Its native range runs from Kenya into northeast Tanzania. It grows in tropical lands with a dry season. In the wild, it grows on rocky slopes among bushland trees. It also grows in sandy, stony ground there. Records place it about 1,480–4,265 feet [450–1,300 metres] above sea level.

Plants reach about 5–6.6 feet [1.5–2 metres] tall. Branches may stand upright or lie on the ground. Those that touch soil can take root. The slim stems have few branches near their tops. They have clear colour marks. Each stem has four, sometimes five, angles and rather flat sides. Slight dips in stem width mark where past growth periods ended. Paired spines may be short or almost absent. Small prickles near the leaf scars vary, even on one branch.

The yellow flower parts, called cyathia, span about 0.24 inches. They grow in small, simple groups with oblong nectar glands. These glands have a long shape. The small fruit is a pale tan capsule. It has lobes with sharp outlines. Its curved stalk holds it well beyond the flower group. This helps tell the species apart from its close relatives. The egg-shaped seeds have small bumps on their surface.

This plant cannot bear frost and needs warmth. It suits USDA zones 10–11. LLIFLE advises sun to light shade. Useful Tropical Plants favours light shade. Deep shade can make stems pale and stretched, with weak growth. Strong light brings out the marks on the stems. Use an airy potting mix made up largely of mineral matter. The mix must let water drain freely. Water while the plant grows, but leave no water round its roots. Keep the mix nearly dry in winter. It copes with drought and grows fast in its growing season. Poor watering and airflow can cause rot.

Gardeners grow it for its marked stems and compact, branching shape. It grows in pots and can spend warm summers outdoors. Cuttings root with ease once cut ends dry for several days. Planting fresh cuts too soon can cause rot. Useful Tropical Plants notes local use of wild plants as medicine. People use the latex, roots, stems, and leaves. These uses do not prove that they are safe or helpful. That source lists no food uses or other practical uses. LLIFLE warns that the sap is poisonous and can irritate skin. Useful Tropical Plants gives a broader warning about spurge latex. It warns that this latex can cause serious eye injury.