Knotweed

Parts Usually Used

Flowering herb, fresh or dried

Description of Plant(s) and Culture

Knotgrass is an annual plant; the creeping, prostrate stem bears alternate, sessile, lanceolate leaves that narrow at the base, which is covered by brownish, sheathing, knotlike stipules. At the base of each leaf is a jagged, silvery sheath. The axillary flowers, growing all along the stem, are small, green and white or green with pink or purple margins. Flowering time is from June to October.

Blossoms are followed by brown, three-sided fruits in dried petals. Other varieties: Smartweed or water pepper (P. hydropiper); Water smartweed (P. punctatum); Lady’s thumb, Doorweed, Heartsease, Heartweed, Pinkweed, Redleg, Spotted knotweed (P. persicaria).

Where Found

Found in waste places, roadsides, yards, and cultivated soils all over the world. Also found on shores and around salt marshes. Culpeper tells us that Knotgrass or Knotweed grows in every country of this land.

Medicinal Properties

Astringent, diuretic, hemostatic, vulnerary

Biochemical Information

Volatile oils, silica, mucilage, tannins, and various flavonic derivatives, quercitol, salicylic acid, and kaempferol

Legends, Myths and Stories

Knotgrass has been used in China as a medicinal for lung ailments since the second millennium BC. A strong tea held in the mouth for 5 minutes relieves toothache and stops bleeding gums. Prolonged use is said to harden loose, spongy gums and make teeth less sensitive. Helps prevent tooth decay.

Uses

Historical herbals recommended knotweed for digestive complaints such as diarrhea, dysentery, and enteritis, as well as for respiratory afflictions including bronchitis, whooping cough, and general lung ailments. Herbalists also employed the plant as a blood coagulant for internal bleeding and stomach ulcers, and administered it for jaundice, rheumatism, intestinal worms, inflammations, swellings, toothache, and piles.

The fresh juice was traditionally applied to bleeding gums, wounds, and nosebleeds, while various preparations were used topically for canker sores, ulcers, and general sores. Additionally, folk traditions utilized teas and tinctures of knotgrass with the belief that they would dissolve gravel and urinary stones, or act as a general blood purifier.

Bibliography

The Herb Book , by John Lust, Bantam Books, 666 Fifth Avenue, New York, NY. copyright 1974. Chinese Medicinal Herbs , compiled by Shih-Chen Li, Georgetown Press, San Francisco, California, 1973. , Lotus Press, PO Box 325, Twin Lakes. , West Nyack, NY, 1987. , 15 Columbus Circle, New York, NY 10023 An Instant Guide to Medicinal Plants , by Pamela Forey and Ruth Lindsay, Crescent Books (January 27, 1992).