Prostrate knotweed

Encyclopedia Article

Prostrate knotweed                       Polygonum aviculare L.

Family: Polygonaceae (Smartweed family)
Life cycle: Annual
Habitat: Turf, landscapes, compacted soils
Native status: Introduced from Europe

General description: Prostrate to ascending growth habit with stems up to 2 ft long. Stems are wiry, branched, and swollen at nodes. Leaves alternate, lanceolate to elliptic, pointed at tip, usually less than ¾” long. Ochrea surrounds stem at leaf nodes. Flowers inconspicuous in axillary clusters.

Key ID traits: Prostrate growth, alternate, elliptic leaves with ochrea. Presence in areas with compacted soil.

Similar species: Prostrate spurge has similar growth habit, but has opposite leaves and milky sap.

Miscellaneous: Normally found in areas with highly compacted soils, such as gravel driveways and adjacent to sidewalks. One of the first summer annuals to emerge.

Weed Factsheet Index

Typical habitat of prostrate knotweed - compacted soils. Plants have prostrate, wiry stems with small, eliptic leaves.

The cotyledons of prostrate knotweed are linear and erect. One of the earliest emerging summer annuals, typically appears in early March in central Iowa and continues emerging for long period.


Leaves are eliptic to lanceolate shaped, typically less than 0.5 inches long.