Purple Loosestrife

Purple Loosestrife still troubling on the Eagle River Chain

Purple Loosestrife

Purple Loosestrife, an aquatic invasive species, is present on the Eagle River Chain. It is native to Europe and Asia where insects and diseases native to those areas have kept it in check. It was introduced to North America as a garden plant but has since spread to wild areas and depleted natural habitat for native plants and animals.

Purple Loosestrife grows taller and faster than our native wetland plants. It displaces native vegetation and degrades wildlife habitat. Eventually, Purple Loosestrife can overrun wetlands thousands of acres in size, and almost entirely eliminate the open water habitat. The plant can be detrimental to recreation by choking off waterways. Thick growth of Purple Loosestrife may impede boat travel.

Purple Loosestrife is a perennial herb 3-7 feet tall with a dense busy growth of 1-50 stems. The stems, which range from green to purple, die back each year. Showy flowers on numerous long spikes vary from purple to magenta. It blooms from July to September.

Prevention is the easiest control method and the best way to stop the spread of Purple Loosestrife. Monitor your shoreline annually and remove any new young plants. Plants are most easily located when flowering. One mature PL plant produces over 2 million seeds a season, so learn to recognize pre-flowering plants or search for them when they just start to bloom. Destroy plants before they flower and drop seeds. When removing plants, take care not to leave stems or cuttings that can resprout or disperse viable seed.

In 2012, a biocontrol program utilizing Galerucella beetles was begun and repeated in 2013, 2014 and 2016. It is the hope that this program will become self-sustaining over the years and eventually halt the growth and spread of purple loosestrife.

Each summer a core group of ERCLA volunteers surveys the entire Chain and notes the locations with GPS coordinates. Volunteers for Cranberry Lake are Carole Linn and Chrysa Murphy.

A map showing the location of Purple loosestrife on the Eagle River Chain in 2016 is available. Click here to view the map.

We are in need of volunteers to monitor the purple loosestrife, so please consider helping. You need not be a year 'round resident. Click here to volunteer.

Additional information can be found at the following websites:


Purple Loosestrife