Senna siamea aka Siamese Cassia

Senna siamea is an evergreen tree in the pea family, Fabaceae. Common names include Siamese senna, kassod tree, and minjiri. Kew gives its native range as Sri Lanka and Indo-China. It grows in lowland forests, including secondary woods on plains. People grow it across the tropics for shade and wood. Useful Tropical Plants reports its conservation status as Least Concern.

Garden size is about 39–49 feet [12–15 metres] tall. Some trees reach 59 feet [18 metres]. PFAF gives a spread of 39 feet [12 metres]. Young trees have a dense crown with a rounded shape. Older crowns spread out, with uneven growth and drooping branches. The trunk is short and straight. Dark green leaves grow alternately along the stems. Each pinnate leaf consists of several smaller leaflets. Yellow flowers form at branch tips. Black seedpods have thick edges.

This fast-growing tree suits warm lowland sites with a monsoon climate. It grows in sun or light shade and prefers moist soil. Good drainage matters, though it accepts sand, loam, and clay. It can also grow in poor soil. Its soil pH range runs from very acid to mildly alkaline. In dry regions, roots need access to groundwater. PFAF lists USDA zones 9–12 for this species. Long dry seasons can limit growth where groundwater is out of reach.

Growers use the tree to shade roads and crop plantations. It shelters cocoa, coffee, and tea from the sun. Dense plantings serve as windbreaks, hedges, and living fences. Hedgerows help water enter the soil and reduce runoff. Leaves supply mulch and green manure. The wood provides fuel, charcoal, and timber for furniture. Sources disagree about weed risk: PFAF says no, while Useful Tropical Plants says yes. Neither supplied account gives details of pests or diseases.

Leaves, flowers, and young fruits have food uses, but safety needs care. PFAF warns that plant parts can poison people when eaten. It describes changing the cooking water three times to remove toxins. Flowers and young fruits feature in curries. Traditional remedies use the fruit for intestinal worms and heartwood as a laxative. These records describe past uses, not proof of safe treatment. Sawdust can irritate the eyes, nose, and throat. A yellow powder from the wood may also irritate skin.