Prostrate Knotweed

Prostrate Knotweed

Polygonum aviculare L.

Polygonaceae (Smartweed Family)

▲ seedling

▲ ▼ young plants

▲ mature plants

▲ ▼ mature plants showing prostrate growth habit

Knotweeds:

• usually more of a turf or vegetable crop weed; summer annuals
• inflorescences in the axils of leaves, very tiny
• knotweed: (pp. 484-485, Weeds of the Great Plains; not in Weeds of the Northeast)
  • is a wiry annual weed with small leaves, found in lawns, gardens
  • has tiny white flowers in axils of the leaves
• prostrate knotweed:
  • is similar to regular knotweed, but internodes much closer, and plant has spreading habit and can tolerate close mowing
  • has tiny white flowers in axils of the leaves
  • prefers dry, compacted soils
  • looks similar to prostrate spurge, but has no milky juice
• other small-leaved knotweed species may occur occasionally
  • erect knotweed: similar to prostrate knotweed, but with more rounded to rounded-oval shaped leaves
  • bushy knotweed: leaves similar to prostrate knotweed, but stems grow 3-4 feet tall, very straight
• annual knotweeds controlled by tillage (same precautions as smartweeds), some with pre-emergent herbicides or more with post-emergent herbicides

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