Prostrate Knotweed
Polygonum aviculare

Prostrate knotweed is a low-growing summer annual found in lawns throughout the United States. It grows well in heavily trafficked areas. A long taproot allows it to survive hot, dry periods. The branching stems form a dense mat that can be 2 to 3 feet wide.

You will often find knotweed in sports fields, paths, driveways, and along roadsides…it grows and thrives in hard, compacted soils.

It can be confused with Spotted Spurge. However, the spurges ooze a milky sap when their stems are cut.

Lawn weed ID Prostrate Knotweed
Knotweed Flower - Polygonum aviculare
Image By Grezty [Public domain], from Wikimedia Commons


  • Low-growing summer annual
  • Found in hard, compact soils
  • Appears in early spring
  • Knotty stem
  • Alternate leaf arrangement
  • Young plants have long, slender green leaves. Mature plants have smaller dull green leaves
  • A paper-like sheath (ocrea) circles the stem at the base of the leaves.
  • Tiny rose to white colored flowers

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