Perennial herb mostly to about 1 m or more tall. Lower leaves stalked, lanceolate to about 30 cm long, 8 cm wide. Flowers in close-set whorls or branched clusters; spring to summer. Fruit valves 3-6 mm long with a small wart at the base. Fruit stalks 3-6 mm long, thin, with joint in lower half.
Europe, SW Asia
Common weed of gardens and waysides, especially on moist or boggy ground, naturalised in all Australian States. Noxious in Western Australia and Tasmania.
Source: (1997). Polygonaceae. In: . Horticultural Flora of South-eastern Australia. Volume 2. Flowering plants. Dicotyledons. Part 1. The identification of garden and cultivated plants. University of New South Wales Press.