Purple Loosestrife

 Purple loosestrife Lythrum salicaria


 Where did purple loosestrife come from?

  • Purple loosestrife is an invasive wetland perennial from Europe and Asia.
  • Introduced in the early 1800s to North America via ship ballast, as a medicinal herb, and ornamental plant.

 What does purple loosestrife look like?

  •  Loosestrife plants grow from four to ten feet high, depending upon conditions, and produce a showy display of magenta-colored flower spikes throughout much of the summer Purple loosestrife is an erect perennial herb, with a square, woody stem and opposite or whorled leaves.
  • Flowers have five to seven petals.
  • Leaves are lance-shaped, stalkless, and heart-shaped or rounded at the base.
  • Mature plants can have from 30 to 50 stems arising from a single rootstock.

 Why is purple loosestrife a problem?

  • Each plant may produce over one million seeds, which can remain viable for several years.
  • Seeds can be moved by water, vehicles, and wildlife.
  • Loosestrife often spreads to additional wetland sites.
  • Loosestrife restricts native wetland plant species, including some federally endangered orchids, and reduces habitat for waterfowl.

 How do we control purple loosestrife?

  • Purple loosestrife cannot be transported into or within the State of Kansas.
  • Small infestations of young purple loosestrife plants may be pulled by hand, preferably before seed set.
  • For older plants, spot treating with a herbicide is recommended.
  • These herbicides may be most effective when applied late in the season when plants are preparing for dormancy. However, it may be best to do a mid-summer and a late season treatment, to reduce the amount of seed produced.
  • Research is currently being conducted to determine possible control by insects.
  • Contact your local Kansas Department of Agriculture office for more information.
  • Early detection of isolated populations may help prevent their spread. Your help to report new sightings and to prevent their spread is vital.


 What do I do if I find purple loosestrife?

  Images and Recent news

 Purple Loosestrife links:

Kansas Department of Agriculture-purple loosestrife

USDA Plant Profile

NPS loosestrife page

Plant Profile