Reynoutria japonica
Reynoutria japonica
Safety & Hazards
Although no specific mention has been made for this species, there have been reports that some members of this genus can cause photosensitivity in susceptible people. Many species also contain oxalic acid (the distinctive lemony flavour of sorrel) - whilst not toxic this substance can bind up other minerals making them unavailable to the body and leading to mineral deficiency. Having said that, a number of common foods such as sorrel and rhubarb contain oxalic acid and the leaves of most members of this genus are nutritious and beneficial to eat in moderate quantities. Cooking the leaves will reduce their content of oxalic acid. People with a tendency to rheumatism, arthritis, gout, kidney stones or hyperacidity should take especial caution if including this plant in their diet since it can aggravate their condition[ 238 Title Encyclopaedia of Herbs and their Uses. Publication Author Bown. D. Publisher Dorling Kindersley, London. Year 1995 ISBN 0-7513-020-31 Description A very well presented and informative book on herbs from around the globe. Plenty in it for both the casual reader and the serious student. Just one main quibble is the silly way of having two separate entries for each plant. ].
Botanical Description
Reynoutria japonica is a perennial plant that can grow up to 3.00 metres tall. The plant is harvested from the wild for local use as a food, medicine and source of materials. Japanese knotweed is an extremely invasive plant capable of sending up new shoots at a considerable distance from the main clump and also of growing up through tarmac[ 200 Title The New RHS Dictionary of Gardening. 1992. Publication Author Huxley. A. Publisher MacMillan Press Year 1992 ISBN 0-333-47494-5 Description Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed. ]. The sub-species cuspidatum is the form that is most likely to cause problems. It is considered to be a pest in many areas, where it is forming large clumps in the wild and out-competing native species.