Purple Loosestrife

purple-loosestrife-flower
purple-loosestrife-habitat

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.

Treatment Timeline


JanFebMarAprMayJuneJulyAugSeptOctNovDec
Control











RemovalNot recommended - plants regrow from stem and root fragments
Herbicide











Growth











Vegetative











Flowering











Seed