Origin: Tropical Asia
Originally from China, mimosa or silk tree was introduced to the United States in 1745 and cultivated since the 18th century primarily for use as an ornamental. Mimosa remains a popular ornamental because of its fragrant and showy flowers. Mimosa grows and reproduces along roadways and disturbed areas and readily establishes after escaping from cultivation.
Mimosa is a strong competitor in open areas or forest edges. It can grow in various soil types, produces large amounts of seed, and resprouts when cut back or damaged. Mimosa reduces sunlight and nutrients available to desired species because of the denseness of the stand. An opportunist, mimosa will take advantage of disturbed areas, either spreading by seed or germinating in contaminated soil. Mimosa is often seen along roadsides and open vacant lots in urban/suburban areas and can become a problem along banks of waterways, where its seeds are easily transported in water.
The first step in preventative control of mimosa is to limit planting and removal of existing plants within the landscape. If possible, removal should occur before seeds are produced. Care must be exercised to prevent seed spread and dispersal during the removal process.
Hand-pull seedlings and remove seedpods, if possible. There are many native plants that make excellent alternatives to mimosa. These include serviceberry (Amelanchier arborea), sweet acacia (Acacia farnesiana), redbud (Cercis canadensis), flowering dogwood (Cornus florida), river birch (Betula nigra), fringe tree (Chionanthus virginicus), American holly (Ilex opaca), and sweetgum (Liquidambar styraciflua).
Mimosa can be controlled using a variety of mechanical controls. Power or manual saws can be used to cut trees at ground level. Control is best achieved at flowering before seed production. Cutting is an initial control measure and will require either an herbicidal control or repeated cutting for resprouts. Cutting is most effective when trees have begun to flower to prevent seed production, but may require repeated cuts or an herbicide application to control sprouting.
In the case where herbicide use is impractical, girdling can be effective on larger trees. Make a cut through the bark encircling the base of the tree, approximately six inches above the ground, ensuring the cut goes well below the bark. This will kill the top of the tree but the tree may resprout and require a follow-up treatment with an herbicide. Hand pulling will effectively control young seedlings. Plants should be pulled as soon as possible to prevent maturation. The entire root must be removed since broken fragments may resprout.
There are no known biological control agents for mimosa.