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Purple Loosestrife

Lythrum salicaria

Purple loosestrife has spikes of bright purple or magenta flowers that bloom in mid- to late summer. (Jenn Forman Orth/Flickr)
Purple loosestrife has spikes of bright purple or magenta flowers that bloom in mid- to late summer. (Jenn Forman Orth/Flickr)

Purple loosestrife is a non-native, invasive perennial plant with spikes of bright purple flowers that bloom in mid- to late summer.

Appearance:

  • Spikes of bright purple or magenta flowers
  • Flowers bloom in July-September
  • Square, six-sided stems
  • Long or lance-shaped leaves that grow up to 4 inches long
  • Leaves are arranged in pairs or whorls of three along the stems
  • In autumn, leaves often turn red for about two weeks before fading and falling off
  • Can grow to 6 feet tall

Habitat:

  • Found in disturbed fresh and brackish wetlands and other moist or marshy sites, including ditches, roadsides, wet meadows, and along the edges of ponds, rivers and reservoirs
  • Grows in colonies

Range:

  • Found throughout the Chesapeake Bay watershed
  • Native to Europe and Asia

Reproduction and Life Cycle:

  • Spreads rapidly via seeds, roots and stem fragments
  • A single mature plant can produce more than 2 million seeds per year
  • Wind, water and animals spread the seeds, which grow into new seedlings the following spring
  • Can reproduce asexually when its thick, fleshy roots produce new shoots, allowing the plant to spread about one foot per year
  • New plants can also grow from stem fragments when plants are cut or mowed down

Other Facts:

  • Spread to the U.S. in the 18th and 19th centuries when ships inadvertently carried the plant’s tiny seeds in their ballast and shipments. Purple loosestrife was also introduced purposefully in certain areas because of its beauty and value as a healing herb.
  • Purple loosestrife is considered to be invasive because it grows rapidly, produces many seeds and has no natural predators. The plant quickly establishes itself and crowds out native wetland plants.
  • Never plant any variety of purple loosestrife in your garden. Even seed-free varieties can cross-breed with invasive strains to make seeds.

Sources and Additional Information:




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