Purple loosestrife is a wetland plant from Europe and Asia. It was introduced into the east coast of North America in the 1800s. First spreading along roads, canals, and drainage ditches, then later distributed as an ornamental, this exotic plant is in 40 states and all Canadian border provinces.
Purple loosestrife invades marshes and lakeshores, replacing cattails and other wetland plants. The plant can form dense, impenetrable stands which are unsuitable as cover, food, or nesting sites for a wide range of native wetland animals including ducks, geese, rails, bitterns, muskrats, frogs, toads, and turtles. Many rare and endangered wetland plants and animals are also at risk.
Currently there are about 2,000 purple loosestrife infestations recorded in 77 of Minnesota's 87 counties. Of those sites, the majority (70%) are lakes, rivers, or wetlands. Inventory totals indicate that Minnesota presently has over 58,000 acres infested with purple loosestrife.
Likely means of spread: Seeds escape from gardens and nurseries into wetlands, lakes, and rivers. Once in aquatic systems, seeds are easily spread by moving water and wetland animals.
Purple loosestrife (Lythrum salicaria, L. virgatum and any combination thereof) is listed as a MDA Prohibited Noxious Weed (Control List) and a prohibited invasive species in Minnesota. It is illegal to possess, plant, transport, or sell purple loosestrife in Minnesota.