- Lythrum virgatum, Purple loosestrife is an erect, herbaceous, perennial wetland weed. One of the more recognizable features of purple loosestrife is its square-shaped stems. They are woody, and can be either smooth or covered with downy hairs. Stems have short, slender branches and evenly spaced nodes. Mature plants have up to 30 flowering stems, which can reach a height of 1.6-3.3 ft. (50-100 cm).
- Purple loosestrife leaves are 2-5 in. (5-12 cm) long and narrow with a rounded or heart-shaped base, and smooth-edged. The stalkless leaves are arranged opposite or sometimes alternate along the stem. The lower leaves often form a whorl around the stem.
- The inflorescence of purple loosestrife is a spike of numerous, showy, reddish-purple or magenta flowers set in clusters. Each flower measures about 0.6-0.8 in. (15-20 mm) across, has five to seven petals, and a small, yellow center. Flowering occurs from about April to August.
- Seeds are produced in rounded capsules about 0.24 in. (6 mm) in length. The capsules open to release more than a hundred tiny, light brown seeds about the size of poppy seeds. Water, wind, wildlife, and humans easily spread the lightweight seeds that are shed throughout the winter. Purple loosestrife is a prolific seed producer; a single mature plant can produce several million seeds. When purple loosestrife densities are high, billions of seeds are produced per acre. Seed viability is greater than 90 percent and seeds can remain viable in the soil for many years.
- Ecological Threat
- L. virgatum is commonly found along waterways and other wetland habitats where it replaces native vegetation. It was introduced from Europe during the late 1800s. L. virgatum is native to parts of Europe and temperate Asia.
EDDMapS Distribution - This map is incomplete and is based only on current site and county level reports made by experts, herbaria, and literature. For more information, visit www.eddmaps.org
State Regulated List - This map identifies those states that list this species on their regulated list. For more information, visit Invasive.org
Invasive Listing Sources
- Commonwealth of Pennsylvania, Department of Conservation and Natural Resources, 1994.
- Faith Campbell, 1998
- Mid-Atlantic Exotic Pest Plant Council, 2005
- Minnesota Noxious Weeds
- Nevada Noxious Weeds
- Nonnative Invasive Species in Southern Forest and Grassland Ecosystems
- North Dakota Noxious Weeds
- Tennessee Noxious Weeds
- Virginia Department of Conservation and Recreation, 2009
- Virginia Noxious Weeds
- Washington Noxious Weeds
- WeedUS - Database of Plants Invading Natural Areas in the United States
|Common Name Reference:|| USDA, NRCS. 2010. The PLANTS Database. National Plant Data Center, Baton Rouge, LA, USA.|
|Scientific Name Reference:||USDA, NRCS. 2010. The PLANTS Database. National Plant Data Center, Baton Rouge, LA, USA.|