Purple Loosestrife—Lythrum salicaria
An attractive but invasive perennial, purple loosestrife has become established in a wide range of habitats including river banks, lake and pond shores, irrigation ditches and roadsides.
Plants grow in clumps. Mature plants can have 30 to 50 stems growing from a single rootstock. Flowers are showy and vibrant.
Multiple flowers occur on 4 to 10 foot spikes, with pink-purple petals and yellow centers. Each plant produces one to three million seeds, which remain viable for several years.
Purple loosestrife invades many wetland types where it crowds out native plants and degrades wetland habitat.
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Identification and Control Information
- Purple Loosestrife Control Methods - Maine Natural Areas Prorgram
- Maine Invasive Plants: Purple Loosestrife (PDF) —University of Maine Cooperative Extension
- Tips for Managing Purple Loosestrife (PDF) —Maine Integrated Pest Management Council
- Species Identification Card: Purple Loosestrife (PDF) —Gulf of Maine Research Institute, Vital Signs Program
- Fact Sheet with Description, Management Methods and Links for More Information (PDF) —Massachusetts Department of Conservation and Recreation
- Purple Loosestrife: What you should know, what you can do—Minnesota Sea Grant
- Fact Sheet with Identification Tips and Control Methods (PDF) —King County, Washington Department of Natural Resources and Parks
- Fact Sheet: Purple Loosestrife (PDF) —National Park Service
- Plant Guide: Purple Loosestrife (PDF) —USDA Natural Resources Conservation Services
- Fact Sheet with Description and Management Options (PDF) —Plant Conservation Alliance’s Alien Plant Working Group
- Where Have All the Purple Flowers Gone?—Minnesota Sea Grant
- Alien Plant Invaders of Natural Areas brochure (PDF) —Plant Conservation Alliance
- What the Heck is an Invasive Plant? brochure (PDF) —Plant Conservation Alliance
[Photos, left to right: Joseph M. DiTomaso, University of California - Davis, Bugwood.org; John D. Byrd, Mississippi State University, Bugwood.org; Agriculture and Agri-Food Canada Archive, Agriculture and Agri-Food Canada, Bugwood.org]