Purple loosestrife

Scientific Name: Lythrum salicaria

2007 BS Thurner Hof (commons.wikimedia.org)Copyright Info

Identification: Purple loosestrife is an upright, perennial plant. It may have up to 50 stems emerging from its base, and its leaves are elongated, have smooth edges, and are fuzzy on their surface. Each plant may have numerous flower spikes made up of many flowers. The flowers are rose-purple and have five to seven petals. Its fruit is smaller than 0.1 of an inch (2 mm) in diameter and is 0.16 of an inch (3-4 mm) long with many small, powdery seeds. The plant is also known as purple lythrum, spiked loosestrife, salicaire, bouquet violet, and rainbow weed.

Size: This plant can grow up to 8 feet (2.5 m) tall, forming colonies 5 feet (1.5 m) or more in width.

Native Range: Purple loosestrife is native to Eurasia. It extends from Great Britain to central Russia, North Africa, Japan, Korea, southeast Asia, northern India, and the northern Himalayan region.

Table 1. Great Lakes region nonindigenous occurrences, the earliest and latest observations in each state/province, and the tally and names of HUCs with observations†. Names and dates are hyperlinked to their relevant specimen records. The list of references for all nonindigenous occurrences of Lythrum salicaria are found here.

Full list of USGS occurrences

State/ProvinceYear of earliest observationYear of last observationTotal HUCs with observations†HUCs with observations†
Indiana191420142Little Calumet-Galien; St. Joseph
Michigan1839201969Au Gres-Rifle; Au Sable; Bad-Montreal; Betsie-Platte; Betsy-Chocolay; Birch-Willow; Black; Black-Macatawa; Black-Presque Isle; Boardman-Charlevoix; Brevoort-Millecoquins; Brule; Carp-Pine; Cass; Cedar-Ford; Cheboygan; Clinton; Dead-Kelsey; Detroit; Escanaba; Fishdam-Sturgeon; Flint; Great Lakes Region; Huron; Kalamazoo; Kawkawlin-Pine; Keweenaw Peninsula; Lake Erie; Lake Huron; Lake Michigan; Lake St. Clair; Lake Superior; Little Calumet-Galien; Lone Lake-Ocqueoc; Lower Grand; Manistee; Manistique; Maple; Menominee; Michigamme; Muskegon; Northeastern Lake Michigan; Northwestern Lake Huron; Northwestern Lake Michigan; Ontonagon; Ottawa-Stony; Pere Marquette-White; Pigeon-Wiscoggin; Pine; Raisin; Saginaw; Shiawassee; Southeastern Lake Michigan; Southwestern Lake Huron; St. Clair; St. Clair-Detroit; St. Joseph; St. Joseph; St. Marys; Sturgeon; Tacoosh-Whitefish; Tahquamenon; Thornapple; Thunder Bay; Tiffin; Tittabawassee; Upper Grand; Waiska; Western Lake Erie
Minnesota198720185Baptism-Brule; Beartrap-Nemadji; Beaver-Lester; Cloquet; St. Louis
New York1869201715Buffalo-Eighteenmile; Cattaraugus; Chaumont-Perch; Irondequoit-Ninemile; Lake Ontario; Lower Genesee; Mettawee River; Niagara; Oak Orchard-Twelvemile; Oneida; Oswego; Salmon-Sandy; Saranac River; Seneca; St. Lawrence
Ohio1902201910Auglaize; Black-Rocky; Blanchard; Cedar-Portage; Cuyahoga; Lake Erie; Lower Maumee; Sandusky; Southern Lake Erie; Western Lake Erie
Pennsylvania200820121Lake Erie
Vermont189820192Lake Champlain; Otter Creek
Wisconsin1928201824Bad-Montreal; Beartrap-Nemadji; Black-Presque Isle; Brule; Door-Kewaunee; Duck-Pensaukee; Fox; Lake Michigan; Lake Superior; Lake Winnebago; Lower Fox; Manitowoc-Sheboygan; Menominee; Milwaukee; Northwestern Lake Michigan; Northwestern Lake Michigan; Oconto; Ontonagon; Peshtigo; Pike-Root; Southwestern Lake Superior; St. Louis; Upper Fox; Wolf

Table last updated 12/24/2019

† Populations may not be currently present.

* HUCs are not listed for areas where the observation(s) cannot be approximated to a HUC (e.g. state centroids or Canadian provinces).

Means of Introduction: In the early 1880s, purple loosestrife was introduced into North America through the discharge of water and sand from transoceanic ships. It was also brought to the United States as an ornamental landscape plant. Its seeds are generally dispersed by water, but they can also spread by wind and by mud attached to wildlife, livestock, vehicle tires, boats, and people. In states where the plant is permitted, horticulturists continue to promote purple loosestrife as a landscape plant and as a food supply for bees. It was probably spread throughout the Great Lakes via the waterways flowing through this region.

Status: This species is now in every state except Florida and can also be found in Australia, Tasmania, and New Zealand. Its first Great Lakes sighting was near Lake Ontario in 1869.

Remarks: Purple loosestrife has been labeled the “purple plague” because of its widespread devastation to natural communities. The species is included on the Nature Conservancy’s list of “America’s Least Wanted –The Dirty Dozen.” More than thirty states, including Illinois, Indiana, Michigan, Minnesota, Ohio, Pennsylvania and Wisconsin, have passed legislation restricting or prohibiting the plant’s importation and sale.

Four insect species – a root-mining weevil, two leaf beetles, and a flower-feeding weevil – feed on purple loosestrife and are used to control the plant’s spread.

Author: Illinois-Indiana Sea Grant

Contributing Agencies:
NOAA Sea Grant GLRI Logo

Revision Date: 4/24/2012

Citation for this information:
Illinois-Indiana Sea Grant, 2020, Purple loosestrife: U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, and NOAA Great Lakes Aquatic Nonindigenous Species Information System, Ann Arbor, MI, https://nas.er.usgs.gov/queries/greatlakes/FactSheet.aspx?SpeciesID=239&Potential=N&Type=1&HUCNumber=DGreatLakes, Revision Date: 4/24/2012, Access Date: 1/20/2020

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.