Albizia lebbeck

Common name: East Indian walnut

Other common names: Broome raintree, Frywood, Koko, Lebbek, Indian sirus, Lebbektree, Rattlepod, Siristree, Woman's tongue, Woman's tongue tree

Names in non-English languages: Philippines India


East Indian Walnut or Siris, as it's known in India, is a deciduous timber, fodder and landscape tree originating from the Indian subcontinent and Southeast Asia. Its natural range extends from Pakistan through India to Bangladesh and Burma. 

In native forests, it may reach up to 30 m (100 ft) tall with a straight trunk and narrow crown. On open sites, it is more typically 10 to 20 m (30 to 60 ft) tall with a short trunk supporting a large, rounded, wide-spreading crown. The bark is grey-brown, smooth on young trees, becoming fissured and rough.

Leaves are up to 25 cm (10 in) long and twice-feathered, consisting of deep green oblong leaflets arranged in pairs along each leaf branch. They fall from the tree in the dry season, leaving the branches bare until the rainy season when new leaves emerge and grow to fill out the branches again.

The flowers resemble powder puffs with long greenish filaments and are sweetly fragrant. They bloom when the dry season transitions to the rainy season, coinciding with new leaf growth. 

Fertilised flowers develop into flat, papery seedpods that turn light grey-brown when mature and persist on the tree for many months, well into the next dry season.

Darwin, Australia




The heartwood is attractive, resembling brown walnut with its characteristic black and grey streaks. However, the weight, durability, and general quality vary considerably among trees grown at different rates. Slow-growing trees generally produce a heavier, more durable, high-quality wood than fast-growing trees.

In the tropics, tree growth rates are strongly influenced by moisture availability, with growth rates generally increasing with increasing rainfall. As a result, wood density and natural resistance vary considerably, ranging from 500 to 800 kgs per cubic meter (31 to 50 lbs per cubic ft) and from non-resistant to moderately resistant.

Well-formed logs are sawn into planks used for flooring, furniture,  joinery work and cabinets. Selected logs are sliced for decorative veneer. Small diameter lengths and branchwood are cut for fuelwood, both firewood and charcoal. 

Although rich in nectar, the structure of the flower makes it difficult for honeybees to gain access, which limits its importance as a honey plant.

The fresh leaves and seedpods are used as a livestock feed and have a reported crude protein content of about 20% of their dry weight.

It is commonly planted to shade coffee (Coffea arabica) and tea (Camellia sinensis) and for environmental services such as preventing soil erosion, partly because of its nitrogen-fixing abilities and tolerance to adverse growing conditions. It is also sometimes cultivated in gardens and landscapes for the shade it gives and for its showy, fragrant flowers.


Grows naturally in sub-humid to humid subtropical and tropical climates, generally areas with annual lows of 16 to 25°C, annual highs of 27 to 37°C, annual rainfall of 400 to 2500 mm and a dry season of 2 to 8 months, extending to 12 months with irrigation or groundwater. However, it reaches its best development as a timber tree in areas with annual rainfall of 1300 mm or more.


New plants are usually started from seed, which are pretreated before sowing by immersing them for a few seconds in boiling water that is then allowed to cool. It performs best on moist to dry, free-draining loam and sand soils of a slightly acid to alkaline nature, generally with a pH of  5.0 to 8.5. It has good tolerance to drought, seasonal flooding, soil salt and limestone soil conditions.

Problem features

The seedpods are produced in large quantities and are easily dispersed by wind and water. It is listed in more than one reference publication as a serious weed and is assessed as a high weed risk for Hawaii and Florida, respectively, by the Hawaii Pacific Weed Risk Assessment project (HPWRA) and by the IFAS Assessment of Non-Native Plants in Florida's Natural Areas. Root-suckering also contributes to its weediness.

Pollen released by the flowers is reported to cause hay fever in some, and the dust from sawn wood irritates the nasal passage.

Where it grows

With irrigation or groundwater



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