Purple Loosestrife is a perennial that can grow from two to seven feet tall. Leaves are opposite each other and it has small purple flowers at the top of a four-sided stem. Purple loosestrife is a native of Europe and Asia and was accidentally brought to the east coast of the United States by immigrants in the ballast of ships and in the wool of sheep during the 1800's. This type of seed transportation is how purple loosestrife came to the Midwest in the 1880's and to Illinois by the 1940's and 1950's. Purple loosestrife will invade a moist area making it unfavorable for native species to grow, and will form such a dense cluster that is unsuitable for cover, nest sites, or food for many wetland species.
Eradication is extremely difficult due to the fact that it becomes invasive if disturbed or if the water level is lowered. It also produces many thousands of seeds per plant, reproduces from broken stems or roots, and seeds can lay dormant until conditions improve for germination. In additions, purple loosestrife has no natural predators in North America. Attempts to destroy plants by herbicides, burning, or pulling have been quite unsuccessful. Since 1994, three beetle species who feed only on purple loosestrife and a weevil were imported from Europe, propagated here in the States, and then released are showing good results in consuming large quantities of plants. Purple loosestrife is listed under the Illinois Exotic which prohibits the sale or distribution of purple loosestrife without a permit. (Information provided by the Illinois Department of Natural Resources and the University of Illinois)
