Small deciduous tree up to 12(–18) m tall, frequently multistemmed; stems usually straight, sometimes branching low, up to 40(–100) cm in diameter; bark deeply fissured, pale grey to dark grey or dark brown; crown narrow, dense, with upwards growing branches and drooping foliage. Leaves alternate, clustered at ends of twigs, pendent, imparipinnately compound with 3–7 pairs of leaflets, up to 28 cm long; stipules awl-shaped, minute; leaflets opposite, stalked, lanceolate, 4–8 cm × 1–2 cm, asymmetrical and slightly curved, tapering to a sharp point, margins minutely toothed, glabrescent. Inflorescence a terminal raceme up to 30 cm long, pendent, many-flowered. Flowers bisexual, papilionaceous, almost scentless; pedicel c. 1.5 cm long; calyx broadly campanulate, c. 8 mm long, 5-lobed; corolla c. 2 cm long, violet-blue with a white spot inside standard; stamens 10, free; ovary superior, oblong-linear, densely hairy, 1-celled, style curved. Fruit an oblong-linear pod 7–10 cm long, flattened, pale brown, later becoming grey or blackish, tardily dehiscent, 3–8-seeded. Seeds ovoid, flattened, c. 6 mm × 4 mm, smooth and shiny, yellow-brown.

Emetic (root decoction)

Bolusanthus speciosus

A leaf decoction is drunk to stop vomiting. A root decoction is drunk to treat abdominal complaints. The roots are used to treat stomach-ache. The dried inner bark to treat abdominal cramps.