Prostrate knotweed is a low-growing plant with wiry stems and a thin taproot. Plants branch extensively at the base, with branches lying along the ground but not rooting. The alternate, blue-green leaves are narrow, typically not exceeding an inch in length and 1/4 inch in width. Leaf tips may be slightly pointed to rounded in outline. The petioles are very short. The greenish-white flowers are borne in leaf axils and are inconspicuous.

Habitat

Prostrate knotweed is commonly found on compacted soils and may occur on waste areas, or in lawns, paths, and other areas in yards. It is frequently a problem on compacted or high-traffic areas in lawns.

Management Options

Non-Chemical Management

Cultivation (rototilling or hoeing) will effectively eliminate plants.

Select non-chemical management options as your first choice!

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides

Apply according to label directions. Glyphosate and glufosinate products should be applied as spot treatments only! NOTE: Some ingredients listed here are only available in combination. Read the label carefully on combination products to make sure the product is suitable for your specific situation.

Landscape areas

glyphosate
dichlobenil
glufosinate
trifluralin
products containing diquat

Turf areas

2,4-D + MCPP + dicamba

Bare ground areas

glyphosate
products containing diquat

Images

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Caption: Prostrate knotweed leaves Photo by: R. Parker
Caption: Prostrate knotweed Photo by: R. Parker
Caption: Prostrate knotweed flowers and leaf axils Photo by: D.G. Swan
Caption: Prostrate knotweed seedling Photo by: J.A. Kropf
Caption: Prostrate knotweed growing in gravel Photo by: T.W. Miller
Caption: Prostrate knotweed flowers and nodes Photo by: T. W. Miller
Caption: Prostrate knotweed leaves Photo by: T. W. Miller

WSU Extension

Hortsense