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?
- If you discover purple loosestrife, note the date and location, and contact your local Kansas Department of Agriculture office, the Emporia Research Office at (620) 342-0658, or email the Aquatic Nuisance Species Coordinator
Purple Loosestrife links: