Small group of yellow flag along the water.

Control Yellow Flag

Many people ask how to get rid of yellow flag. The following options can be considered for how to control yellow flag.


Manual/Mechanical Control:

If you are considering how to remove yellow flag, physically cutting this plant and digging up the rhizomes can be a somewhat effective method of control.


Herbicide Control:

There are multiple options for how to kill yellow flag that offer some control.

  1. Dibrox (for ponds or lakes) – liquid that is diluted with water and sprayed over the plants, fast acting.
  2. Cattail and Water Lily Control (Imox + surfactant) (for ponds or lakes) – liquids that are mixed and diluted with water and sprayed over the plants.


Treatment Tips:

When treating yellow flag,

  • With Imox or other systemic herbicides, 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.
  • Treat when the plants are established and actively growing.
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