Japanese Knotweed Tincture (Fallopia japonica)BOTANICAL NAME Fallopia japonica Reynoutria japonica Polygonum cuspidatum COMMON NAMES Japanese Knotweed, Hu Zhang A traditional botanical extract made from the root of Fallopia japonica (also known as Japanese knotweed), prepared as a 1: 3 tincture in sugar beet alcohol. Often used in herbal traditions, this supplement is valued for its natural antioxidant content and forms part of many bespoke blends prepared by herbalists.