Invasive Species: Garden Yellow Loosestrife

Lysimachia vulgaris

Garden yellow loosestrife is an escaped ornamental.

Why is it important to control?

Loosestrife is an aggressive invader of riparian areas, crowding out native species. Infestations can clog waterways and increase sedimentation.

How can you identify it?

Opposite leaves and a round stemGarden yellow loosestrife seedheads
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 yellow and are arranged on long showy spikes. Seeds found in dry, egg-shaped capsules
Bloom Time: July to August

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 no biocontrol agents.

How to report it?

There are various ways you can report this noxious weed.

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