Control Smartweed

Generally, the different types of smartweed look similar. Treating varieties of smartweed is the same. The following options can be considered for how to control smartweed.

Click here to read more about identifying this plant.

Manual/Mechanical Control:

If you are considering how to remove smartweed, physically cutting this plant and digging up the roots can be a somewhat effective method of control. However, physical control can be difficult. Smartweed can re-grow from any roots or seeds remaining in the area.

Herbicide Control:

There are a few options for how to kill smartweed that offer great control.

1. Cattail and Water Lily Control (Imox + surfactant) (for ponds or lakes) – liquids that are mixed and diluted with water and sprayed directly on the plants.
2. Liquid 2, 4-D (for ponds or lakes) – liquid that is diluted with water and sprayed directly on the plants. Most effective on treatment areas larger than a half-acre; this allows longer contact exposure time.

Treatment Tips:

When treating smartweed,

• Treat when the plants are established and actively growing.
• With Imox or other systemic herbicides like 2, 4-D, treatment is most effective when the plants are mature or close to full grown. This allows for more plant surface to spray enough mixture on.
  • Treat in late summer to early fall to get better kill of the root systems. At this time, plants are pulling energy into their roots to store for the winter.