Purple Loosestrife

purple loosestrife plant
purple loosestrife flower
purple loosestrife near road
purple loosestrife near creek

Purple Loosestrife

Lythrum salicaria

Information Sheet (PDF)


Colorado List A - Eradication required in Jefferson County

General

  • Family: Lythraceae
  • Has been sold as an ornamental but no longer available in Colorado
  • Introduced from Europe


Habitat

  • Infestations are found in wetlands; displaces native species; Reduces waterfowl habitat
  • Perennial forb
  • Prefers a moist, organic soil but tolerates a wide range of soils
  • Prefers sun but tolerates up to 50 percent shade


Plant


Vegetation

  • Mature plants are 6 to 8 feet tall
  • Narrow leaves attached closely to the stem


Roots

  • Tap root with woody lateral branches


Flower

  • 2 to 3 million seeds per year
  • Color: rose-purple on spike-shaped inflorescence
  • Season: June to September


Seedling

  • Germinates in spring


Reproduction

  • Cut stems
  • Root fragments
  • Seed


Control


Biological

  • Not allowed; eradication is required


Chemical


Cultural

  • Hand pulling young plants before seed set
  • Prevention - maintain health of site


Mechanical

  • Burning - N/A
  • Grazing - N/A
  • Mowing - Not recommended; will spread seed and plants resprout


Use all chemicals according to the manufacturer's label. No specific recommendation or endorsement is made or implied by listing methods or products.