Medicinal Herbs

Japanese Knotweed Root Extract

Reynoutria japonica

Japanese knotweed (Reynoutria japonica) is a perennial that sends up hairless stems half a metre to a metre tall, occasionally to two, flecked along stem and branch with purple-pink. The broad oval leaves are alternate and short-stalked, dark brownish-green above and paler beneath; sprays of tiny white flowers rise from the leaf axils in late summer. It grows wild on hills and roadsides, most abundantly around Sapa, and is planted in the lowlands for its root. Roots are dug in autumn, trimmed, washed and cut into short pieces or sliced, then dried: yellow-brown outside, yellow at the cut, faintly bitter and with little smell.