Invasive Species: Purple Loosestrife

Lythrum salicaria

Hailing from Eurasia, Purple loosestrife was introduced to the east coast of North America in the 1800s.

Why is it important to control?

Loosestrife is a serious invader of wetlands, rendering them unsuitable for waterfowl and other birds.

How can you identify it?

Closeup photo of leaves of purple loosestrifeFlower closeup
Habitat: Wet soils such as wetlands, marshes and riparian areas
Life Cycle: Perennial
Height: Up to 6.5ft
Leaf Description: Lance-shaped leaves are arranged opposite or whorls of three
Fruit & Flower Description: Flowers are usually magenta but can be pink or white and are arranged on long showy spikes. Seeds are extremely small
Bloom Time: July to September

How do you control it?

  • For small areas, digging out is the best method. Do this before they set fruit.

  • Make sure to remove the entire root system and throw any plant material away in a tied plastic bag in the trash.

  • Removing flowers early in the blooming season can help prevent seed dispersal. Avoid cutting flower spikes with mature seed capsules.

  • The Oregon Department of Agriculture has four biocontrol agents, two leaf beetles, a root weevil and a seed weevil. They are well established in Oregon.

How to report it?

There are various ways you can report this noxious weed.

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