Invasive Species: Water Primrose and Floating Primrose-Willow

Ludwigia hexapetala

Ludwigia peploides

Water primrose is an invasive aquatic species that forms extensive mats, impairing water flow and shoreline activity.

Why is it important to control?

It can dominate shoreline vegetation if introduced to lakes, rivers, ponds or streams. It is very difficult to control once established.

How can you identify it?

Close up image of Ludwigia hexapetala flower
Habitat: Shallow, slow moving water
Life Cycle: Perennial
Height: Submerged stems up to 6 ft
Leaf Description: Leaves on stems without flowers are oblong. Leaves on flowering stems are lance-shaped.
Fruit & Flower Description: Bright yellow flowers
Bloom Time: July to September

How do you control it?

  • Small patches can be hand pulled with careful and persistent effort.

  • Dispose of plant materials in a tied plastic bag. Put the bag in the trash.

  • Contact a licensed applicator for herbicide application.

  • The Oregon Department of Agriculture has no approved biocontrols.

How to report it?

There are various ways you can report this noxious weed.

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