Albizia lebbeck aka Siris Tree

Albizia lebbeck is a fast-growing, deciduous tree in the pea family, Fabaceae. Common names include siris tree, East Indian walnut, and woman's tongue tree. Its native range runs from the Indian subcontinent to Myanmar. It grows in tropical and subtropical savannahs and sandy river beds. Its home climate has distinct wet and dry seasons.

In cultivation, it reaches about 49–66 feet [15–20 metres] tall. Some trees reach 98 feet [30 metres]. One garden source gives a spread of 49 feet [15 metres]. Its broad, open crown casts shade over a wide area. The trunk is straight and round in cross-section. Its bipinnate leaves divide into smaller groups of leaflets. Each leaf has one to four pairs of pinnae. Each pinna bears six to eighteen leaflets. The white flowers have many stamens and a strong scent. Bees and other insects pollinate them, and the tree is self-fertile. The fruit forms a pod with six to twelve seeds.

Grow this tree in full sun, with soil that drains well. It accepts sandy, loamy, and clay soils, including poor ground. It tolerates a wide pH range and saline soil. Dry or moist soil suits it. It can establish where rainfall is low and erratic. It also grows in humid tropical areas. It is frost-tender, with a listed USDA range of zones 10–11. Wind exposure is a concern because its limbs can break.

People plant siris for shade in gardens and public spaces. Growers also use it to shade coffee and cocoa. It fixes nitrogen, and its leaves supply mulch and green manure. Its wide, shallow roots help hold soil on eroded sites. The wood supplies timber, fuel, and charcoal. Other uses include fodder, dye, gum, and soap. Yet the tree sheds much litter beneath its crown. It can also invade land beyond its native range.

Sources list leaves, seeds, and shoots as edible parts. Young shoot tips are boiled before eating. This limited food use does not make every part safe. The bark serves as a fish poison. Bark dye can irritate skin, while wood dust can irritate the nose and throat. The pods contain saponins. Traditional medicine uses several parts, including bark, leaves, seeds, and flowers.