The mimosa tree (Albizia julibrissin) also goes by the names silk tree or silky acacia. Approximately 50 types of mimosa trees exist worldwide. Introduced to the United States in 1745, they have since been cultivated for ornamental use by homeowners and landscapers who plant them near decks, terraces and patios.
Mimosas can be found in nature from the Middle East to Asia and in the eucalypti forests of Australia. Although they're not native in the United States, you'll find naturalized mimosa trees in California and from Louisiana to New Jersey.
Flower, Fruit and Foliage
Aromatic pink flowers grow about 2 inches long on the end of the tree's branches; they resemble miniature pom-poms. Yellow, flat pods measure up to 6 inches long and hold five to 10 seeds. These oval seeds are light brown and half an inch long. The green leaves, which grow 5 to 8 inches long, look like feathers and alternate on the lime-green stems.
Mimosas prefer full sun, although they can tolerate partial shade. They can grow in a variety of well-drained soil types such as clay, loam and sand, and they flourish in acidic to slightly alkaline conditions. They need water only occasionally. As drought-tolerant and low-salt-tolerant plants, they grow best in U.S. hardiness zones six through nine.
Habitat and Threat
You'll find silk trees planted along roadsides and forest edges, in open urban and suburban areas, on water banks and in disturbed areas, where they spread because of seed transport or seeds from nearby mimosas. Their ability to grow in various soil conditions, combined with their seed proliferation, makes these trees a danger to their neighbors. Because of their dense stands, they reduce nutrients and sunlight to other trees and plants.
Pests and Disease
Cottony cushion scales, mites and web worms can make mimosa trees their shelter. Silky acacias can also suffer from wilt, which might prove fatal to the tree and spread to nearby mimosas through their root systems.