Bolusanthus speciosus aka Tree Wisteria

Bolusanthus speciosus is a tree in the pea family, Fabaceae. Its common names include tree wisteria and elephant wood. It comes from southern tropical Africa and southern Africa. Its range includes Angola, Zambia, Zimbabwe, Mozambique, Botswana, Eswatini and South Africa. It grows in open savannah and wooded grassland. Trees stand alone or in groups, seldom in dense thickets.

This tree has a slim, upright crown. It sheds its leaves or keeps some through the year. It can also grow as a shrub. Usual heights reach 13–33 feet [4–10 metres]. Exceptional trees reach about 59 feet [18 metres]. One or more straight trunks support the crown. The trunks often branch close to the ground. Most reach about 1.3 feet [0.4 metres] across. Rare trunks reach about 3.3 feet [1 metre] across.

The flowers hang in loose bunches from the branches. They have a pea-like shape, a scent, and blue-mauve tones. A strong display can cover much of the tree. The flowering season is brief, despite this striking show. Insects pollinate the flowers. Gardeners grow the tree for its flowers and upright form. Its growth rate is medium to moderately fast. With good care, yearly growth can reach 2.6 feet [0.8 metres].

Give this tree a sunny site in a warm climate. It grows in tropical and subtropical lowlands. It accepts several soil types but favours fertile, heavier soils. Its preferred soil pH runs from 6.5 to 8. Established trees withstand drought. Preferred yearly rainfall falls between 500 and 650 millimetres. Cold limits where gardeners can grow it. Temperatures of −5°C or lower can kill mature trees. Even 2°C can badly harm young growth.

People harvest the tree for timber and local medicinal use. Its hard, heavy wood lasts well and turns well. Carpenters use it for furniture, tool handles and household goods. The timber resists termites and pinhole borers. Traditional remedies use inner bark and roots for stomach complaints. Some root preparations serve as emetics. Researchers have found compounds with antimicrobial activity in its wood and bark. These findings do not establish safe home use. The source lists no known food uses or hazards. That does not confirm that every part is safe to eat.