Bistort, Meadow bistort, Snakeweed

Polygonum bistorta

Physical Characteristics

Polygonum bistorta is a PERENNIAL growing to 0.5 m (1ft 8in) by 0.5 m (1ft 8in) at a fast rate. See above for USDA hardiness. It is hardy to UK zone 4. It is in flower from June to September, and the seeds ripen from August to October. The species is hermaphrodite (has both male and female organs) and is pollinated by Insects. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils and can grow in very acid soils. It can grow in semi-shade (light woodland) or no shade. It prefers moist or wet soil.

Distribution

Northern and central Europe, including Britain, mountains of S. Europe, western and central Asia.

Habitats

Meadow; Bog Garden; Cultivated Beds;

Edible Uses

Edible Parts: Leaves Root Seed Edible Uses: Leaves - raw or cooked[2, 7, 9, 103]. One report says that they are rather bitter[5], but we have found them to have a fairly mild flavour, especially when the leaves are young, though the texture is somewhat chewy when they are eaten raw[7, K]. They make an excellent substitute for spinach[183]. In Northern England the leaves are an ingredient of a bitter Lenten pudding, called Easter ledger pudding, that is eaten at Lent[183]. The leaves are available from late winter in most years and can be eaten until the early autumn though they become much tougher as the season progresses[K]. The leaves are a good source of vitamins A and C[257], a nutritional analysis is available[218]. Seed - raw or cooked[172]. The seed is very small and rather fiddly to utilize[K]. Root - raw or cooked[7, 172, 257]. Rich in starch and tannin, it is steeped in water and then roasted in order to reduce the tannin content[4, 115]. It is then said to be a tasty and nutritious food[4]. The root has also been boiled or used in soups and stews[183] and can be dried then ground into a powder and used in making bread[4]. The root contains 30% starch, 1% calcium oxalate and 15 - 36% tannin[218].

Medicinal Uses

Antidiarrhoeal Astringent Cholera Demulcent Diuretic Dysentery Epilepsy Febrifuge Laxative Styptic Bistort is one of the most strongly astringent of all herbs and it is used to contract tissues and staunch blood flow[254]. The root is powerfully astringent, demulcent, diuretic, febrifuge, laxative and strongly styptic[4, 218]. It is gathered in early spring when the leaves are just beginning to shoot, and then dried[4]. It is much used, both internally and externally, in the treatment of internal and external bleeding, diarrhoea, dysentery, cholera etc[4, 9, 13, 21, 147, 165, 172]. It is also taken internally in the treatment of a wide range of complaints including catarrh, cystitis, irritable bowel syndrome, peptic ulcers, ulcerative colitis and excessive menstruation[238, 254]. Externally, it makes a good wash for small burns and wounds, and is used to treat pharyngitis, stomatitis, vaginal discharge, anal fissure etc[238, 254]. A mouth wash or gargle is used to treat spongy gums, mouth ulcers and sore throats[254]. The leaves are astringent and have a great reputation in the treatment of wounds[4]. In Chinese medicine the rhizome is used for: epilepsy, fever, tetanus, carbuncles, snake and mosquito bites, scrofula and cramps in hands and feet [301]. Considered useful in diabetes [301].

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[238].