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?
- 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.
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