15. Silk Tree

(Albizia julibrissin)

Other Common Names: Pink Acacia, Mimosa Tree, Nemu Tree, Pink Siris, Bastard Tamarind, Lenkoran Acacia.

Family: Fabaceae,
Subfamily: Mimosoideae

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Silk Tree's showy blossoms during the height of summer makes up for its tardiness to waken from winter dormancy. A large old specimen is on your left as you face the HUB lawn and a younger one to the right. The rarefied lightness of its frond-like leaflets and its bright pink flower puffs make it unmistakable. Silk Tree is named from its threadlike flowers and is unrelated to the mulberry tree from which silk is produced. It is native over much of Asia and now grows wild in the eastern United States where it was introduced in 1785. Although it produces many seedpods in Seattle, it rarely springs up wild here.


Each night and while it rains, the leaves of the silk tree close slowly, the leaflets bowing down as if the tree was sleeping. The synonym nemu tree is an adaptation of the Japanese name nemunki, meaning sleeping tree. The silk-like flowers are attractive to bees, butterflies, and hummingbirds. In the wild this tree tends to grow in dry plains, sandy valleys and uplands. It can tolerate strong winds but cannot grow in the shade.  The bark or cortex is used to cure bruises and as a vermicide. The wood of the silk tree is dense, hard, and strong and has been used to make furniture.

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