He Huan Pi
Botanical name: Albizia julibrissin
Common name: Silk tree bark, Albizia bark, Mimosa
Literal name translation: conjoined happiness bark
Family: Fabaceae, pea family
Part used in Chinese medicine: bark
Major Chinese medicine actions:
Relieves constraint, calms spirit, harmonizes blood, stops pain,
regulates qi, invigorates blood, dissipates swelling
Photo Credits: (top to bottom)
Photo 1: Albizia julibrissin; 05/2005; author Fanghong; permission under GFDL
Photo 2: Albizia julibrissin; author Kurt Stueber; permission under GFDL
Photo 3: Albizia julibrissin; author Kurt Stueber; permission under GFDL
The silk tree, also called mimosa tree, is a fast growing small deciduous tree commonly cultivated as an ornamental in warm climates for its pretty silky pink flowers and graceful feathery leaves. It is indigenous to Western and Eastern Asia, from Iran to China, growing to 40 feet high and blooming in June through July. After blooming, 6-inch long pea-shaped seedpods are formed.
The leaves are edible and considered food suitable in famine times. The flowers attract hummingbirds and leaves are light sensitive, folding up at night. He Huan, its Chinese name, means “conjoined happiness”, indicating the symbolism of its leaves folding like a couple in bed at night.
Growing and Propagation
The tree grows best in full sun and will not do well in shade. It is very adaptable and can tolerate poor soil, high pH, salinity, high winds, drought, and cold temperatures down to about -10 F, though the tips of branches may freeze in very cold conditions. The young growth in spring, even on mature plants, is frost-tender and so it is best to grow the plants in a position sheltered from the early morning sun. The tree is hardy in USDA zones 6 to 9.
When growing from seed, they should first be pre-soaked in hot water for 24 hours, or scarified with a file or sandpaper and then soaked for 8-10 hours. The soil should be kept moist until the seed sprout, which takes about 10 days. Trees can also be propagated by cuttings.
Harvesting and Preparation
For medicinal use, the lateral branches may be cut off in the spring, summer or fall and the bark stripped. It is said that the best quality bark is harvested before April 5, which is the time of the Qing Ming Festival. The bark is covered with a wet cloth to make sure it is uniformly moist, then cut into pieces and dried in the sun. The flowers buds (He Huan Hua) are also used in Chinese medicine and are harvested from May to July.