Johnsongrass

Photo of Johnson grass flower clustersPhoto

Images: Seed heads on mature johnsongrass plants (above; Missouri Dept of Conservation). Johnsongrass spreads through rhizomes (below).

Johnsongrass is a widespread weed throughout the US, with herbicide resistant populations in the midwest, south, and mid-Atlantic. Effective control involves targeting the seedlings before they have a chance to develop the rhizomes, which are quickly-spreading and more difficult to control.

Resistant populations:

  • Group 1 (phenylpyrazolin, fops, dims)
  • Group 2 (ALS)
  • Group 3
  • Group 9 (glyphosate)

Locations of resistant populations:

Arkansas, Mississippi, Nebraska, Tennessee, Texas, Virginia (Search by State to see which resistant populations are in each state)

Resources:

Control of johnsongrass in fields, pastures, and conservation areas – Missouri Dept of Conservation