Albizia odoratissima: Black siris

Family: Fabaceae
Common name: Black siris, Ceylon rosewood, Fragrant albizia, Kala siris, Tea shade tree, Fragrant black siris, Bhilwara

Black siris trees are good shade trees for gardens, parks, lakeshores, roadsides, and agricultural land since they are fast-growing. These trees can grow to a height of 20-25 meters with a heavily branched and rounded crown.

The trunk is short with horizontal stripes, reaching a diameter of 1-1.5 meters in fully grown trees. Black siris leaves droop down from the branches and are dark green in color. They are bipinnate, each leaf divided into 3-9 pairs of secondary leaflets and further into 20-30 pairs of tertiary leaflets which are oval, 2-3 cms long.

Flowers are fluffy clusters of white pom-poms which turn yellow as they get older, and are fragrant giving the plant its name Fragrant Albizia. These fragrant flowers are pollinated by ants, insects, and butterflies.

Once pollinated, they form long, flat pods which are 20-30 cms long containing 10-14 brown seeds. The seed pods turn dark brown and split open on maturity, releasing the seeds. Black siris trees prefer warm, tropical weather, full sunlight, and moist, well-drained soil. They can grow up to a meter a year making them ideal shade trees for landscaped areas. The lovely white flowers covering the tree adds to its beauty.

Belonging to the pea family of Fabaceae, these trees have Rhizobium bacteriae in their roots, that can absorb atmospheric nitrogen and convert them into nitrates and nitrites which can be absorbed by plants. Black siris trees thus enrich the soil around them, making them a favorite shade tree especially for those plants that need filtered sunlight, like tea and coffee.

They are drought-resistant and need very little care once they are established in the soil. Black siris trees are also used for reforestation since they can grow and propagate very quickly.

They are a native of Asian countries like India, Srilanka, Bangladesh, Nepal, Vietnam, and China. The bark of the tree is used to make wine. This tree also produces low-quality gum and a brown dye.

Wood is dark brown and sturdy with bands of lighter and darker wood. It is used to make kitchen cabinets, paneling, cartwheels, and construction timber. Leaves are used as fodder and wood is burnt as fuel. Parts of the tree are used in the treatment of cough, bronchitis, leprosy, diabetes, ulcers, and skin diseases.

Propagation is through seeds.