Common knotweed (Polygonum arenastrum) is a very low growing prostrate weed that will grow on hard, compacted soils. It is a short-lived perennial with wiry stems. The nodes on the stems are slightly swollen which gives it the "knot" appearance. It is sometimes confused with spotted spurge.


As with most lawn weeds, the best control is to grow a healthy, vigorous turfgrass. A good layer of mulch such as shredded bark or wood chips will help manage weeds in the bed or border.

If cultural options do not provide enough control, several herbicides are also labeled for this weed, however, this one falls under the "difficult to control" lawn weeds and may be tough to eliminate.


Note: We have provided some general information and observations on this topic aimed at the home gardener. Before you take any serious action in your landscape, check with your state's land grant university's Cooperative Extension Service for the most current, appropriate, localized recommendations.


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