Prostrate Knotweed

Polygonaceae

LIFE FORM: Summer annual

NATIVITY: Eurasia

VEGETATIVE CHARACTERISTICS:

Plants form a tough, wiry mat; alternate leaves are lanceolate, an inch or less long, with pointed tips; a papery sheath encircles the stem at the base of each leaf (ocrea).

FLOWERS:

Inconspicuous flowers are produced from June though September.

FRUIT/DISPERSAL AGENTS:

Self-sows readily.

ECOLOGICAL PREFERENCE:

This plant is most often found on hard, compacted soils with heavy foot traffic; trampled lawns in public parks; neglected residential and commercial landscapes; minimally maintained public parks and open space; small-scale pavement openings (tree pits) and cracks; rock outcrops and stone walls.

ENVIRONMENTAL FUNCTION:

Disturbance-adapted colonizer.

CULTURAL SIGNIFICANCE:

This plant flourishes in pavement cracks where nothing else can grow; it is the quintessential urban survivor. Listed by John Josselyn in New-England’s Rarities, published in 1672, under the category: “Of such plants as have sprung up since the English planted and kept cattle in New England.”