Knotweed

Polygonum aviculare

COMMON NAMES

• Armstrong
• Bian Xu
• Cowgrass
• Knotgrass
• Knotweed
• Nine Joints
• Pigweed

Knotweed - an annual herb that usually grows prostrate, sending out straggly stems, 6-12 inches long, that form a thick mat. Narrow elliptical to oval leaves, 1/4 - 1/2 inch long, issue alternately from joints, or "knots," on the stems. Tiny flower clusters (June-November), produced in the leaf axils, are pale green or pink to purple.

Knotweed has been used as a diuretic in Chinese herbal medicine for over 2,000 years. In the Western tradition, the 1st-century AD physician Dioscorides likewise considered the herb a diuretic, as well as a remedy for heavy menstrual bleeding and snake bite.

Knotweed can hold its own as a food, too. Birds are happy with its seeds, and both pigs and cattle like it -hence the alternative names pigweed and cowgrass. In a pinch, humans too have used this weed (a member of the buckwheat family) for nourishment by pounding the seeds into meal.

PARTS USED

Aerial parts.

USES

A herb with astringent and diuretic properties, knotweed is used in European herbal medicine to treat diarrhea and hemorrhoids, to expel worms, to staunch bleeding wounds, to reduce heavy menstrual flow, and to stop nosebleeds. Knotweed is also taken for pulmonary complaints since its silicic acid content helps strengthen connective tissue within the lungs. In the Chinese tradition, knotweed is given for intestinal worms, to " treat diarrhea and dysentery, and as a diuretic, particularly in cases of painful urination.

HABITAT AND CULTIVATION

Knotweed is found in temperate regions throughout the world. Knotweed thrives in open areas and along shorelines. Knotweed is gathered throughout the summer.

RESEARCH

Chinese research indicates that the herb is a useful medicine for bacillary dysentery. Of 108 people with this disease treated with a paste of knotweed (taken internally), 104 recovered within 5 days.

CONSTITUENTS

Knotweed contains tannins, flavonoids, polyphenols, silicic acid (about 1%), and mucilage.

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