Senna didymobotrya aka African Senna

Senna didymobotrya is an African shrub in the pea family. People call it popcorn bush or candelabra tree. Its home range runs from Ethiopia into southern tropical Africa. It grows in grassland with trees and in evergreen bushland. These sites are often near rivers. It also grows on disturbed ground in these habitats. People have brought it to tropical Asia and the Americas.

This woody shrub grows upright and has several stems. It can also grow as a small tree. It sheds its leaves rather than keeping them year-round. Reported heights range from 1.6–16 feet [0.5–5 metres]. Some plants reach 30 feet [9 metres]. Another source lists a height of 11.5 feet [3.5 metres]. In Chicago, summer growth can reach about 6 feet [1.8 metres]. Each green leaf has several leaflets along its stalk. Crushed leaves give off a scent like popcorn.

Dark buds open into bright yellow flowers. Each bloom measures about 0.17 feet [0.05 metres] across. The flower spikes reach about 1 foot [0.3 metres] long. Dark green-black bracts stand out against the yellow blooms. Chicago Botanic Garden lists blooms from May through October. Reports from the tropics describe two strong bursts of bloom each year. The plant forms seedpods, and insects pollinate its flowers. It can set seed with its own pollen. It also draws both birds and butterflies.

Grow this shrub in full sun with moderate water. It suits tropical and subtropical climates and USDA zones 10–11. Its fast growth needs space in beds and borders. The blooms and bold leaves give these beds a tropical look. Growers also use it for shade, ground cover, and green manure. It has spread beyond gardens and shows invasive traits in some places. Hard seed coats need treatment to help seeds take up water. Scratching the coat can help seeds sprout. A warm-water treatment can also help.

The supplied sources list no edible uses. The plant is poisonous despite its long use as medicine. Preparations made from any part can cause severe vomiting and diarrhoea. Poisoning can be fatal. Leaves and pods contain compounds linked to its laxative effects. People also use the plant as a fish poison. Flowers, bark, leaves, and pods yield dyes for fibres. People use the wood as fuel and for small crafts.