purple loosestrife: Lythrum salicaria (Myrtales: Lythraceae): Invasive Plant Atlas of the United States

purple loosestrife	USDA PLANTS Symbol: LYSA2 U.S. Nativity: Exotic Habit: Aquatic Plants Forbs/Herbs
Lythrum salicaria L.

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Taxonomic Rank: Magnoliopsida: Myrtales: Lythraceae
Synonym(s): purple lythrum, rainbow weed, salicaire, spiked loosestrife
Native Range: Europe (); Old World (BAIL)
Appearance Lythrum salicaria is a tall, multistemmed (30-50 per plant), perennial forb that can grow up to 10 ft. (3 m) in height. Foliage 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. Flowers 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. Fruit Fruits are capsules that are enclosed in the hairy sepals and contain several reddish brown seeds. Ecological Threat Lythrum salicaria is a serious invader of many types of wetlands, including wet meadows, prairie potholes, river and stream banks, lake shores, tidal and nontidal marshes, and ditches. It can quickly form dense stands that completely dominate the area excluding native vegetation. This plant can spread very rapidly due to its prolific seed production; each plant can produce up to 2.5 million seeds per year. It can also hybridize with native loosestrife species, potentially depleting the native species gene pool. Lythrum salicaria is native to Europe and Asia. It was first introduced into North America in the early 1800s for ornamental and medicinal purposes.

Identification, Biology, Control and Management Resources

Best Management Practices - Ontarios Invading Species Awareness Program
Biological Control of Invasive Plants in the Eastern United States - USDA Forest Service
Southeast Exotic Pest Plant Council Invasive Plant Manual - SE-EPPC
Biology and Biological Control of Purple Loosestrife - USDA Forest Service
Weeds Gone Wild: Alien Plant Invaders of Natural Areas - Plant Conservation Alliance
Element Stewardship Abstract - The Nature Conservancy
Weed of the Week - USDA Forest Service
Global Invasive Species Database - Invasive Species Specialist Group
Plant Invaders of Mid-Atlantic Natural Areas - National Park Service and U.S. Fish and Wildlife Service
Best Management Practices - Ontarios Invading Species Awareness Program

Selected Images from Invasive.org

View All Images at Invasive.org

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

EDDMapS Distribution:
This map is incomplete and is based only on current site and county level reports made by experts and records obtained from USDA Plants Database. For more information, visit www.eddmaps.org