Japanese Knotweed

Description

Japanese knotweed is a large, bushy plant, about four to ten feet high, with leaves that are broad, with shortpoints at the tip.  The greenish-white flowers grow in branching spikes. Flowers usually grow from leaf axils, and can be seen from summer to fall (Newcomb 1977).

History

Japanese knotweed was introduced into the New World from Eurasia (Kiple 2000).

The immature stems of Japanese knotweed are used in salads or as a cooked green (Kiple 2000).  Older stalks, peeled, can be used like rhubarb. (Elias 1982)

Current Medicinal Uses

The dried root and stem of Polygonum cuspidatum, also called Hu chang, are used in traditional Chinese medicine to treat high cholesterol and other conditions (Huang 1999). It is also used as a laxative (Lewis 1977).

Polygonum root contains resveratrol (Kimura 2001), the same beneficial phytochemical found in red wine. An aqueous extract of Polygonum cuspidatum showed anti-angiogenesis activity in vitro (Wang 2004).

Adverse Effects

Contact with Japanese knotweed can cause a light-dependent rash in some people (Elias 1982).

References

Elias TS, Dykeman PA. Field Guide to North American Edible Wild Plants. Outdoor Life Books, New York, 1982.

Huang KC. The pharmacology of Chinese herbs, 2nd ed. CRC Press, Boca Raton, 1999: 126.

Wang S, Zheng Z, Weng Y, Yu Y, Zhang D, Fan W, Dai R, Hu Z. Angiogenesis and anti-angiogenesis activity of Chinese medicinal herbal extracts.  Life Sci.  2004 Apr 2;74(20):2467-78. 

Kimura Y, Okuda H. Resveratrol isolated from Polygonum cuspidatum root prevents tumor growth and metastasis to lung and tumor-induced neovascularization in Lewis lung carcinoma-bearing mice. J Nutr.  2001 Jun;131(6):1844-9. 

Kiple KF, Ornelas KC, ed. The Cambridge World History of Food. Cambridge University Press, Cambridge, 2000. (p. 1797)

Lewis WH, Elvin-Lewis MPF. Medical Botany: Plants Affecting Man’s Health. John Wiley & Sons, Inc., New York, 1977. (p. 284)

Newcomb L. Newcomb’s Wildflower Guide. Little, Brown and Company, Boston, 1977. (p. 190)

Disclaimer 

Information on this website is for educational purposes only. Many herbs historically used for medicine are considered too toxic to use today; some of these herbs have caused deaths. Do not ingest these herbs based on information on this website. We have not provided sufficient information for the safe medicinal use of any of these herbs, nor sufficient information for treatment of poisoning. All recreational use of these herbs is dangerous.