IPMP3.0, Oregon State University, Copyright 2000

Biology and Management of Prostrate Knotweed


Registered Herbicides

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    Prostrate Knotweed 

General Description:

Prostrate Knotweed is an annual that reproduces by seed.  Prostrate growing habit with multiple stems 1 to 3 feed in length. Stems swollen at each branch. Stems are bluish-green, leafy, wiry, extending 4 inches to 2 feet in all directions from the small taproot and forming a dense mat.  Leaves bluish-green, alternate, oblong and hairless with papery sheath at leaf base. Clusters of small, pink flowers are produced in leaf axils. Seeds small, slender, reddish-brown, triangular.

Herbicide Control Notes:

  • Gramoxone plus Sinbar or Gramoxone plus Goal provides good control.