Apparently, we have a lot of Japanese knotweed taking over the lot next to our community garden in South Bronx. They don’t know how to get rid of it, we say- they same way humans got rid of many other plants and animals: eat it!
A variegated variety of Japanese Knotweed, used as a landscape plantJapanese knotweed flowers are valued by some beekeepers as an important source of nectar for honeybees, at a time of year when little else is flowering. Japanese knotweed yields a monofloral honey, usually called bamboo honey by northeastern U.S. beekeepers, like a mild-flavored version of buckwheat honey (a related plant also in the Polygonaceae).
The young stems are edible as a spring vegetable, with a flavor similar to mild rhubarb. In some locations, semi-cultivating Japanese knotweed for food has been used as a means of controlling knotweed populations that invade sensitive wetland areas and drive out the native vegetation. Some caution should be exercised when consuming this plant because it, similar to rhubarb, contains oxalic acid, which may aggravate conditions such as rheumatism, arthritis, gout, kidney stones or hyperacidity.
Both Japanese knotweed and giant knotweed are important concentrated sources of resveratrol, replacing grape byproducts. Many large supplement sources of resveratrol now use Japanese knotweed and use its scientific name in the supplement labels. The plant is useful because of its year-round growth and robustness in different climates.
Japanese knotweed is a concentrated source of emodin, used as a nutritional supplement to regulate bowel motility. The roots of Japanese knotweed are used in traditional Chinese and Japanese herbal medicines as a natural laxative. The active principle responsible for the laxative effect is emodin, present in its natural form as a complex of its analogs. Emodin has a mild laxative effect in doses of 20 to 50 mg per day.
Methanol extracts of the roots of Polygonum cuspidatum (Polygonaceae), traditionally used in Korea to maintain oral health, were shown to reduce the viability of Streptococcus mutans and Streptococcus sobrinus as well as inhibit sucrose-dependent adherence, water-insoluble glucan formation, glycolytic acid production and acid tolerance. The authors suggested that inhibitory effects may be mediated by the presence of alkaloids, phenolics, sterols, and terpenes in the extract.