Spread Purple loosestrife spreads primarily by seed, but can also spread from broken-off stems that root themselves in moist soil. Purple loosestrife plants produce over 100,000 seeds a year. These tiny seeds can remain viable in the soil for many years. Although most fall within a few yards of the parent plant, water, animals, boats, construction equipment, and humans can transport seeds long distances. Use of purple loosestrife for gardens and bees probably caused its initial establishment in many areas of Wisconsin.
Any sunny wetland is susceptible to purple loosestrife invasion.
But disturbances such as water drawdowns, damaged vegetation or exposed soil greatly accelerate the process by providing the substrate and sunlight exposure needed for germination. A loosestrife invasion usually begins with a few pioneering plants. These first plants may not spread for several years as they build up a large seed bank in the soil. When the right disturbance occurs, the loosestrife often spreads rapidly and can eventually takeover the entire wetland. Distribution Purple loosestrife can be found throughout Wisconsin, but it is still in low density in most areas.