Synonyms : P. heterophyllum. P. littorale.
Common Name:Birdweed, Pigweed and Lowgrass,Prostrate Knotweed
Habitat :Polygonum aviculare is native to throughout Europe, including Britain, to Temperate Asia. It grows in the waste places, roadsides, railway embankments and the coast. A common garden weed.
A Polygonum aviculare annual with small, elliptic leaves that is primarily found in compacted areas of turfgrass such as pathways or sports fields.
Seedlings: Cotyledons are narrow, linear in outline, often resembling and being mistaken for a grass. The stem below the cotyledons (hypocotyl) is often reddish in color.
Roots: A taproot.
Leaves: Arranged alternately along the stem, lanceolate in outline, approximately 1/2 to 1 1/4 inches long and 1 to 8 mm wide. Leaves have short petioles and a distinctive thin membranous sheath (ocrea) that encircles the stem at the leaf base.
Fruit: A dark red to brown achene.
Stems: Branching, growing prostrate along the ground, ranging from 4 to 24 inches in length. Stems are swollen at the nodes with a thin membranous sheath (ocrea) encircling the stem at each leaf base.
Flowers: Occur in the area between the stems and leaves (leaf axils). From 1 to 5 flowers occur in clusters and are very small and inconspicuous, white to pinkish-white in color.
Edible Uses: Young leaves and plants are eaten raw or cooked. Used as a potherb, they are very rich in zinc. A nutritional analysis is available. Seeds are also eaten raw or cooked. Rather small and fiddly to utilize, they can be used in all the ways that buckwheat (Fagopyrum esculentum) is used, either whole or dried and ground into a powder for use in pancakes, biscuits and piñole. The leaves are a tea substitute.
Succeeds in an ordinary garden soil but prefers a moisture retentive not too fertile soil in sun or part shade. Repays generous treatment, in good soils the plant will cover an area up to a metre in diameter. Prefers an acid soil. Dislikes shade. Knotweed is a common and invasive weed of cultivated ground. It is an important food plant for the caterpillars of many species of butterflies[. It also produces an abundance of seeds and these are a favourite food for many species of birds. Plants seem to be immune to the predations of rabbits. The flowers have little or no scent or honey and are rarely visited by pollinating insects. Self-fertilization is the usual method of reproduction, though cross-fertilization by insects does sometimes occur. The plant also produces cleistogomous flowers – these never open and therefore are always self-fertilized. The plant is very variable and is seen by most botanists as an aggregate species of 4 very variable species, viz. – P. aviculare. L.; P. boreale. (Lange.)Small.; P. rurivacum. Jord. ex Box.; and P. arenastrum. Box.
Seed – sow spring in a cold frame. Germination is usually free and easy. When they are large enough to handle, prick the seedlings out into individual pots and plant them out in the summer if they have reached sufficient size. If not, overwinter them in a cold frame and plant them out the following spring after the last expected frosts. Division in spring or autumn. Very easy, larger divisions can be planted out direct into their permanent positions. We have found that it is better to pot up the smaller divisions and grow them on in light shade in a cold frame until they are well established before planting them out in late spring or early summer.
Figures in grams (g) or miligrams (mg) per 100g of food.
Leaves (Fresh weight)
*0 Calories per 100g
*Water : 81.6%
*Protein: 1.9g; Fat: 0.3g; Carbohydrate: 10.2g; Fibre: 3.5g; Ash: 3.5g;
*Minerals – Calcium: 0mg; Phosphorus: 0mg; Iron: 0mg; Magnesium: 0mg; *Sodium: 0mg; Potassium: 0mg; Zinc: 0mg;
*Vitamins – A: 0mg; Thiamine (B1): 0mg; Riboflavin (B2): 0mg;
*Niacin: 0mg; B6: 0mg; C: 0mg;
The plant is an astringent, coagulant, diuretic and expectorant.
It has been used in the treatment of chronic urinary tract infections. It is claimed to be useful in the prevention of the formation of renal calculi. It stops bleeding and alleviates colics and catarrhs (usually combined with silverweed and ribwort plantain). It is an ingredient in many herbal teas. It operates in the basal metabolism as an adjuvant in diabetic, expectorant and antidiarrheic preparations. It is used to treat bronchitis with bleeding. It is used for pulmonary complaints since its silicic acid content helps strengthen connective tissue within the lungs. It is also used in combination with other herbs to treat rheumatic conditions, gout, and skin disease. It is regarded as a “blood purifying’ remedy. Knotgrass has also been used to treat inflammations of the mucous membranes of the intestinal tract and has been useful in cases of flatulence and biliary insufficiency. Externally it has been used to treat sore throats and vaginal inflammation. Dosage is a decoction of the root from 10-20g to 2 glasses of water, half a glass 3 times a day. Can be used for douches, compresses, rinses. Alcoholic extracts prevent the crystallization of mineral substances in the urine and are antiphlogistic, bacteriostatic and diuretic. Research is being done on the efficacy of the plant in reducing the fragility of blood capillaries, especially in the alimentary canal.
In the Chinese tradition, knotgrass is given for intestinal worms, to treat diarrhea and dysentery, and as a diuretic, particularly in cases of painful urination. Chinese research indicates that the plant is a useful medicine for bacillary dysentery.
Other Uses :……Dye…….Yields a blue dye that is not much inferior to indigo. The part used is not specified, but it is likely to be the leaves. Yellow and green dyes are obtained from the whole plant. The roots contain tannins, but the quantity was not given.
Known Hazards: Although no specific mention has been made for this species, there have been reports that some members of this genus can cause photosensitivity in susceptible people. Many species also contain oxalic acid (the distinctive lemony flavour of sorrel) – whilst not toxic this substance can bind up other minerals making them unavailable to the body and leading to mineral deficiency. Having said that, a number of common foods such as sorrel and rhubarb contain oxalic acid and the leaves of most members of this genus are nutritious and beneficial to eat in moderate quantities. Cooking the leaves will reduce their content of oxalic acid. People with a tendency to rheumatism, arthritis, gout, kidney stones or hyperacidity should take especial caution if including this plant in their diet since it can aggravate their condition.
The information presented herein is intended for educational purposes only. Individual results may vary, and before using any supplements, it is always advisable to consult with your own health care provider.
- Kentucky coffeetree (findmeacure.com)