Chinese Knotweed (Polygonum multiflorum) is an herbaceous perennial vine growing to 2-4 m tall from a woody tuber. The leaves are 3-7 cm long and 2-5 cm broad. The flowers are 6-7 mm diameter, white or greenish-white, produced on short, dense panicles up to 10-20 cm long. The flowering period is from summer to mid-autumn. The fruit is an achene 2.5-3 mm long.