The mimosa tree (Albizia julibrissin) is a deciduous tree from the pea or legume family. Also referred to as silk tree, mimosa blooms with distinctly shaped flowers during a certain time of the year. All the 100 and more species of mimosa are natives of Africa, Asia or Australia. The tree has been used for its ornamental value in Europe and the United States since 18th century.
The pompom-like, airy white or pink flowers of the silk tree bloom from May to July. The 1½- inch-long flowers grow in compound clusters at the base of twigs. The highly fragrant flowers attract honeybees. The silky flowers are followed by seed pods, characteristic of plants from the bean family. The 4-inch-long and 1½- inch-wide pods contain flat seeds that are easily propagated into new plants.
The tree grows up to 35 feet tall and has an umbrella-like open canopy. There are often multiple trunks on a single tree with smooth, light brown bark and arching branches. The foliage measures up to a foot long. The feathery leaves have a main stem with several side branches with ½-inch-long leaflets. Young stems are light green and gradually mature to light brown.
The mimosa tree is classified as an invasive plant by the Florida Exotic Pest Plant Council. The tree spreads in dense stands through prolific seed production and vegetatively, thriving in all soil types and competing vigorously with native vegetation. Mimosa trees resprout readily when damaged or cut and invade disturbed sites, the germination rate undeterred in contaminated soil. The seeds are also transported in water.
Though the mimosa tree is tolerant of areas of partial sun, the tree grows best in full sun. The tree adapts to a variety of soil types, including alkaline. Mimosa is hardy in USDA zones 6 to 9 and grows well even in drought. Scarify the seed before planting for rapid germination. This involves rubbing the seed with a file and soaking in boiling water for a few minutes before planting.