Polygonum cuspidatum, also referred to as Japanese Knotweed and Reynoutria japonica is a large, herbaceous plant , perennial in nature. Japan , China and Korea are its native countries. It belongs to the family Polygonaceae , and consists of hollow stems with distinctly raised nodes which makes it look like a bamboo. The plants of these species are much smaller, though the stems might sometime reach a height of 3–4 m each in the growing season. Its leaves are broad and oval in shape with a truncated base upto14 cm long. The flowers of polygonum cuspidatum are small and creamy white in color. They are known to produce erect racemes which are 6–15 cm long in late summer or early autumn season.

Polygonum cuspidatum is mainly suitable for temperate riparian ecosystems and is mostly found along roadsides and waste places as thick, dense colonies. The longetivity and survival of the species is mainly goes to its ability to tolerate many kinds of soils, pH as well as salinity. Its' roots called rhizomes are known to bear temperatures upto −35 °C. They are also found to grow upto 7 metres horizontally and 3 metres in depth, making its removal from the ground very tough.

Uses:

Polygonum cuspidatum flowers are largely valued by many beekeepers as an important source of nectar for the honeybees. They are known to produce monofloral honey , addressed as bamboo honey beekeepers in the U.S.

Polygonum cuspidatum consists of extremely high content of resveratrol . People involved in the extraction of resveratrol as a supplement source employ Polygonum cuspidatum to get the highest resveratrol concentrations. Its' perennial sturdy growth and ability to survive in different climates makes it the most useful plant for medical use.

Polygonum cuspidatum also consists of high amount of emodin , which is employed as a nutritional supplement to ease bowel motility. The rhizomes of Polygonum cuspidatum are often used in traditional preparation of a natural laxative in Chinese and Japanese cultures.

Preparation :

Polygonum cuspidatum are either consumed by boiling its rhizomes, ground to form a powder or extracted in the form of juice.