purple loosestrife

Myrtales > Lythraceae > Lythrum salicaria L.
Synonym(s): purple lythrum, rainbow weed, salicaire, spiked loosestrife

Purple loosestrife is a tall, multi-stemmed (30-50 per plant), perennial forb that can grow up to 10 ft. (3 m) in height. The opposite or whorled leaves are dark-green, lance-shaped, sessile, 1.5-4 in. (3.8-10.2 cm) long and round or heart-shaped at the base. Flowering occurs in July to October, when pink to purplish flowers develop in 4-16 in. (10.2-40.6 cm) long spikes at the tops of the stems. Flowers have 5-7 petals and twice as many stamens as petals. Fruits are capsules that are enclosed in the hairy sepals. Purple loosestrife is a serious invader of many types of wetlands, including wet meadows, prairie potholes, river and stream banks, lake shores, tidal and non-tidal marshes, and ditches. It can quickly form dense stands that displace native vegetation. Purple loosestrife can spread very rapidly due to its prolific seed production; one plant can produce as many as 2 million seeds per year. Purple loosestrife is native to Europe and Asia. It was first introduced into North America in the early 1800s for ornamental and medicinal purposes. It has also been used as a nectar plant for bee-keeping.


Identification, Biology, Control and Management Resources

  • Weeds of the Week - USDA Forest Service, Northeastern Area, Forest Health Protection

Selected Images from Invasive.org

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Flower(s);
Linda Wilson, University of Idaho, Bugwood.org
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Flower(s);
Eric Coombs, Oregon Department of Agriculture, Bugwood.org
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Flower(s);
Norman E. Rees, USDA Agricultural Research Service, Bugwood.org
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Plant(s); in flower
David Cappaert, Michigan State University, Bugwood.org
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Flower(s);
John D. Byrd, Mississippi State University, Bugwood.org
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Foliage;
Steve Dewey, Utah State University, Bugwood.org
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Fruit(s); fruit and seeds
Gary L. Piper, Washington State University, Bugwood.org
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Plant(s); in flower
John D. Byrd, Mississippi State University, Bugwood.org
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Infestation; Roadside infestation
Britt Slattery, U.S. Fish and Wildlife Service, Bugwood.org
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Plant(s);
Steve Dewey, Utah State University, Bugwood.org
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Infestation;
Steve Dewey, Utah State University, Bugwood.org
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Infestation; Southeast Minnesota, September
Linda Haugen, USDA Forest Service, Bugwood.org
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Infestation;
Steve Dewey, Utah State University, Bugwood.org
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Infestation;
Steve Dewey, Utah State University, Bugwood.org
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Plant(s); Ornamental planting
Steve Dewey, Utah State University, Bugwood.org
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Diagram or Graphic; Britton, N.L., and A. Brown. 1913. Illustrated flora of the northern states and Canada. Vol. 2: 581.
USDA PLANTS Database, USDA NRCS PLANTS Database, Bugwood.org
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Diagram or Graphic; USDA NRCS. Wetland flora: Field office illustrated guide to plant species. USDA Natural Resources Conservation Service.
USDA PLANTS Database, USDA NRCS PLANTS Database, Bugwood.org
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Invasive Reference(s):

Check Invasive.org for most current lists.
  • Alabama - Noxious Weed Law
  • Alabama - IPC List
  • Arizona - Noxious Weed Law
  • Arkansas - Noxious Weed Law
  • California - Noxious Weed Law
  • California - Invasive Plant Inventory
  • Colorado - Noxious Weed Law
  • Connecticut - Noxious Weed Law
  • Iowa - Noxious Weed Law
  • Indiana - Noxious Weed Law
  • Kentucky - EPPC List
  • Massachusetts - Noxious Weed Law
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  • Mississippi - 10 Worst Invasive Weeds
  • Missouri - Noxious Weed Law
  • Montana - Noxious Weed Law
  • Nebraska - Noxious Weed Law
  • New Mexico - Noxious Weed Law
  • Nevada - Noxious Weed Law
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  • Pennsylvania - Noxious Weed Law
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  • South Carolina - EPPC List
  • South Carolina - Noxious Weed Law
  • South Dakota - Noxious Weed Law
  • Tennessee - EPPC List
  • Tennessee - Noxious Weed Law
  • Texas - Noxious Weed Law
  • Texas - Invasive Plant List
  • Utah - Noxious Weed Law
  • Vermont - Noxious Weed Law
  • Virginia - Noxious Weed Law
  • Virginia - Invasive Alien Plant Species
  • Washington - Noxious Weed Law
  • Wisconsin - Noxious Weed Law
  • Wyonming - Noxious Weed Law
  • Mid-Atlantic - EPPC List
  • Invasive Plants: Western North America
  • Invasive Plants: Guide to Identification and the Impacts and Control of Common North American Species
  • Invasive Plants of the Upper Midwest
  • Invasive Plant Atlas of the Mid-South


External Links


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