Persicaria prostrata, basionym Polygonum prostratum, is a species of flowering plant in the family Polygonaceae, native to Australia and perhaps New Zealand. It is known by the common name of creeping knotweed.
Decumbent perennial herb with stems up to about 40 cm long. Leaves lanceolate to narrowly elliptic, 1âÂÂ5 cm long, 3âÂÂ10 mm wide with short hairs on the margins and main veins. Ochreas lobed with hairs 1âÂÂ2 mm long. Compact short cylindrical flower spikes from 0.6âÂÂ4 cm long and 4âÂÂ7 mm diameter.
Persicaria prostrata grows on banks of streams, ground-tanks and ditches and on heavy soils in areas prone to inundation.
The plant was first described in 1810 by Robert Brown as Polygonum prostratum, but was assigned to the genus Persicaria by Jià ÂàSoják in 1974.