The mimosa is a beautiful tree common to the American South. It is often called the silk tree. Native to the Middle East and Asia, it was brought to this country in 1785 by French botanist Andre Micheaux, who planted it in his garden in Charleston, South Carolina. While this attractive tree is loved for its fern-like leaves, fluffy pink flowers, and parasol appearance of branches, all is not love when you also consider the tree’s invasive qualities.
Mimosa is a genus which has more than 400 species of shrubs and herbs. Mimosa pudica, native to South America and southern Central America, is known for its magical show of folding in its leaves when touched or subjected 
to sunlight. Albizia julibrissin, the tree common to the Southeastern United States, also folds in its leaves at night and during rainstorms. Its Persian name means “night sleeper”, and in Japan it is known as the “sleeping tree”.
Leaves of the mimosa are bipinnate, which means that instead of one undivided leaf the leaves are separated like those of a fern or a palm frond. The leaves are composed of one long, slender stem that ranges from 10 to 20 inches long. Each stem is lined with branches, or pinnae. Each pinnae grows opposite the other. The tree is deciduous, which means the leaves drop from the tree in autumn. They do not change color before they drop. The 
complex composition of the leaves gives the tree a light, feathery appearance and add to the appeal of the tree.
Mimosa trees rarely grow taller than 40 feet. Branches grow horizontally on the upper section of the trunk, making the tree appear somewhat like a yard parasol. The tree blooms cottony pink or white flowers June and July on the tips of the tree’s spreading branches. Dangling flat seed pods are produced, which hold an average of eight seeds each. The seeds remain viable for years and are spread by wildlife. Mimosa is also propagated by root sprouts that come up around it, and trees are most often found growing in clusters due to this. The tree is tolerant of poor soil, and this is 
helped by the production of nitrogen in the roots. The mimosa is usually short lived, but this beautiful tree can be very difficult to control once it colonizes property.
Many people avoid the mimosa because of its invasive nature, putting it in the same class as extreme invasives like privet and bradford pear, but I feel problem colonization of this tree is primarily due to neglect. One should be aware of and work with the nature of any tree, for maximum benefit. The tree’s fluffy pink flowers, fern-like leaves, and parasol shape adds a nice, soft touch to landscapes, and gives interest to roadways. This beautiful tree is one of my favorite non-natives.
