And Japanese knotweed rhizomes are a much better source of resveratrol (the antioxidant credited with the causing French Paradox) than red wine . The Japanese name, itadori, means something like "removes pain". They also use the stems as walking sticks, a Japanese friend demonstrated this for me in St Austell last year. Oh and Himalayan balsam contains lots of lawsone, the orange dye found in henna.