Purple Loosestrife

From Great Lakes Wiki

Purple Loosestrife {Lythium Salicaria} is a wetland plant that was introduced to the Great Lakes from Europe in the early 1800’s. The loosestrife has a long purple row of flowers at the top of a stem that can grow up to 8 feet tall, and forms a thick, impenetrable bush. The plants seeds were brought to Michigan through the ballast water of ships traversing the St. Lawrence River, and further spread by people who sold the flowers for their beauty. It also was used for medicinal purposes at one point as it was thought to treat diarrhea, dysentery, wounds, sores, and ulcers.

The Purple Loosestrife can produce 2,700,000 seeds in a single year, and dominates native wetland plants that cannot compete. The loosestrife seeds are spread by aquatic systems and aquatic wildlife. The negative effects on native wildlife are numerous because those species who depend on the native wetland land plants become threatened as the purple loosestrife takes over completely. These species include waterfowl, numerous mammals and aquatic species, and amphibians. Many rare and endangered animals and wetland native plants are threatened as well.

There have been many attempts to control the spread of the purple loosestrife, but most have failed. Conservationists employed a tactic of burning the plants but this method proved to be non-effective because the plants have an underground root system deep beneath the soil which connects them, and simply grows back after a few weeks. Herbicides were not used because they are environmentally degrading. The best way to control this plant is to uproot it completely; however, since this is labor intensive it only works with smaller patches. There are eight species of root mining weevils and leaf eating beetles native to Europe that only feed on the loosestrife, and currently experiments are underway to examine which species would be the most efficient to introduce to Michigan and the greater U.S. in an attempt to control this devastating wetland exotic plant.