Many-stemmed perennial to 2 m tall with branched, reddish bamboo-like stems. Leaves broadly ovate to squarish, to about 12 cm long, 10 cm wide and a base distinctly straight and perpendicular to the stalk, tip pointed and generally elongated. Flowers more or less white in branched slender spikes. Nut 2-4 mm long, glossy brown or black. [Polygonum cuspidatum Sieb. & Zucc., Reynoutria japonica Houtt.]

F. japonica var. compacta (Hook. f.) Buchh. has a smaller overall habit with leaves round to almost square, 5-7 cm long and wide, flowers reddish pink in clusters to about 5 cm long.

Japan

Naturalised in NSW, Victoria and Tasmania.

Leaves mostly truncate at the base and tapered abruptly at the tip to give an extended acuminate point; flowers in slender spikes.

Source: Spencer, R. (1997). Polygonaceae. In: Spencer, R.. 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.