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)

o   is a wiry annual weed with small leaves, found in lawns, gardens

o   has tiny white flowers in axils of the leaves

      prostrate knotweed: 

o   is similar to regular knotweed, but internodes much closer, and plant has spreading habit and can tolerate close mowing

o   has tiny white flowers in axils of the leaves

o   prefers dry, compacted soils

o   looks similar to prostrate spurge, but has no milky juice

      other small-leaved knotweed species may occur occasionally—

o   erect knotweed:  similar to prostrate knotweed, but with more rounded to rounded-oval shaped leaves

o    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