slender knotweed

Persicaria decipiens, commonly known as slender knotweed, is a species of flowering plant native to Australia and Asia.

Persicaria decipiens is a trailing plant whose stems grow horizontally at first but become more vertical with time, reaching 30 cm (1 ft) high. Its narrow elliptic to lanceolate (spear-shaped) leaves are 5–12 cm (2–4.5 in) long and 0.5–1.3 cm (0.20–0.51 in) across. The slender pink flower spikes appear from November to June, with a peak in February. Cylindrical in shape, they are not stiff and tend to bend over. The plant tends to die back in winter and regenerate after rain.