Practical information to identify and manage non-native, invasive plants and animals
The Quiet Invasion:
A Guide to Invasive Species of the Galveston Bay Area
Purple loosestrife
Lythrum salicaria

USDA Symbol:LYSA2
ITIS TSN:27079
Presence:Current Invaders
Habitat:Aquatic
Native Range:Europe and Asia
Toxic Characteristics
This species is not known to be toxic.
Geographic Distribution
Reported in nearly every state in the U.S. Including Texas, but excluding some southeastern states, New Mexico, and Arizona.
Introduction Pathways
Brought to the northeastern United States in the early 1800s as an ornamental and medicinal. Rapidly spread west, colonizing wetlands.
Specific Primary Habitats
Tolerates all kinds of soil, acidic or alkaline, but prefers disturbed organic-rich soil that is exposed. Can thrive in disturbed wetlands with full sun; often found with cattails (Typha latifolia) or sedges.
Identifying Characteristics
A stout perennial herb; stems are generally hairy, becoming woody later in the growing season. Leaves are sessile (without petioles) and range from the base to the midsection of the plant, and are green, mildly hairy, narrow, and long. The inflorescence takes up the terminal end of the plant. Flowers have 5 - 7 petals, are purple, and occur in clusters. Fruit is a small capsule containing around 120 small seeds.
Reproduction Characteristics
A plant may produce 2-3 million seeds per year, which are wind-dispersed. Blooms July through October, and attracts many pollinators including several kinds of bees and butterflies. Also propagates significantly through budding of underground stems.
Growth Characteristics
A single mature plant is capable of growing up to 9 feet in height. Underground stems which produce new buds can grow up to 1 foot per year.
Ecological, Economic, or Social Impact
Purple loosestrife forms dense homogeneous stands, out-competing native vegetation first in wetlands, and later  in uplands. Eliminates native food sources for species of waterfowl and cattle.
Control
Remove small plants including all roots before seed set. Glyphosate is an effective herbicide. Avoid mowing and burning. Avoid "guaranteed sterile" cultivars of purple loosestrife; they are able to cross freely with purple loosestrife.

Native Species Alternatives
Below is a list of alternative plants that are native to the area:
  • Inland seaoats (Chasmanthium latifolium)
  • Spring spiderlily (Hymenocallis liriosme)
  • Louisiana iris (Iris hexagona)
This species belongs to the following lists:
Images
To view a larger version of an image, click on the thumbnail.
Cluster of purple loosestrife. Photo courtesy of Bernd Blossey, Cornell University, www.forestryimages.org Image Number 0002038.
Cluster of purple loosestrife. Photo courtesy of Bernd Blossey, Cornell University, www.forestryimages.org Image Number 0002038.
Infestation of the purple loosestrife in a grassland in the NW U.S. Photo courtesy of Eric Coombs, Oregon Department of Agriculture, www.forestryimages.org; Image Number 0021093.
Infestation of the purple loosestrife in a grassland in the NW U.S. Photo courtesy of Eric Coombs, Oregon Department of Agriculture, www.forestryimages.org; Image Number 0021093.
Single stem of the purple loosestrife showing leaves, flowers, and buds. Photo courtesy of Eric Coombs, Oregon Department of Agriculture, www.forestryimages.org; Image Number 0022075.
Single stem of the purple loosestrife showing leaves, flowers, and buds. Photo courtesy of Eric Coombs, Oregon Department of Agriculture, www.forestryimages.org; Image Number 0022075.
Close-up of flowers of the purple loosestrife. Photo courtesy of Norman E. Rees, USDA Agricultural Research Service, www.forestryimages.org; Image Number 0024065.
Close-up of flowers of the purple loosestrife. Photo courtesy of Norman E. Rees, USDA Agricultural Research Service, www.forestryimages.org; Image Number 0024065.
Plant cluster of the purple loosestrife along a bank. Photo courtesy of USDA APHIS Archives, USDA APHIS, www.forestryimages.org; Image Number 1149038.
Plant cluster of the purple loosestrife along a bank. Photo courtesy of USDA APHIS Archives, USDA APHIS, www.forestryimages.org; Image Number 1149038.
Infestation of the purple loosestrife in 50+ acres of grassland in the NE U.S. Photo courtesy of Randy Westbrooks, U.S. Geological Survey, www.forestryimages.org; Image Number 1299141.
Infestation of the purple loosestrife in 50+ acres of grassland in the NE U.S. Photo courtesy of Randy Westbrooks, U.S. Geological Survey, www.forestryimages.org; Image Number 1299141.
Flowers of purple loosestrife. Photo courtesy of John D. Byrd, Mississippi State University, www.forestryimages.org; Image Number 1391116.
Flowers of purple loosestrife. Photo courtesy of John D. Byrd, Mississippi State University, www.forestryimages.org; Image Number 1391116.
Purple loosestrife in flower. Photo courtesy of Hugh Wilson, Digital Flora of Texas Vascular Plant Image Library, http://www.csdl.tamu.edu.
Purple loosestrife in flower. Photo courtesy of Hugh Wilson, Digital Flora of Texas Vascular Plant Image Library, http://www.csdl.tamu.edu.
Page Updated/Reviewed: 07/14/2010 8:32 AM
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