Thursday, April 26, 2012


Polygonum is represented with 20 species in the Danish wild flora. It is called pileurt (pil= willow), because the leaves look like the leaves of a willow tree.
NB: My sources are from 1979. A few Polygonums have got another Latin name.(mentioned on Wikipedia)

Desolate lake with Amphibious bistort, Hanstholm Reserve, North Jutland.

Polygonum aviculare.
Danish: Vej-pileurt, Hønsegræs
English: Common knot grass, Allseed, Armstrong, Bird's tongue, Centinode, Cowgrass, Hogweed, Sparrow tongue.

Common knot grass

With a very branched and often trailing stem and little red flowers in the corner of the leaves, it was called "this little ugly herb,which is crawling along all roads and paths, is the worst and toughest weed of the street". No other plant has such long and strong roots.  It was named blodurt (bloodherb) from ab. 1450 until the end of the 1500s, and was used against haemorrhages ; spurvetunge (Sparrow tongue ) in ab. 1459, the seeds were eaten by birds, especially tree sparrows; hønsegræs (chicken grass in 1533, because it grows where chicken are; "hundrede knuder" (a hundred knots), the stems are knotted and tough; Sankt Innocens' herb ( 1648-1848), it is not known why it was connected to this Saint; pelsgræs ( fur grass), because it covers the fields of the winter crops like a dense fur coat, but it has many other names: fuglegræs (bird's grass), svinegræs (pig's grass), jerngræs (iron grass), vild boghvede (wild buckwheat) etc. etc.
Polygonum persicaria
Danish: Fersken Pileurt, Ferskenbladet Pileurt
English: Heartweed, Lady's thumb, Redshank, Spotted Lady's thumb.

In DK it was called the Fersken-pileurt (peach -leaved knot grass) because of the familiarity with the leaves of a peach-tree; it has red stems and very swollen joints. The leaves have often a small darkbrown spot in the middle. The small pink flowers are placed in tight spikes. It is common in cultivated, sligthly moist soil.  
It was called loppeurt (flea herb) in 1546-1821 and used against fleas, it was called rødknæ in Jutland, which is related to the English name redshank, maybe because it grew in reddish bog- or swamp-water.

Polygonum convolvolus
Danish: Snerle-pileurt
English: Black Bindweed

It  is common in cultivated land, where the long twining stems with willow- or heart shaped leaves could choke the crops;  it has a triangular nut-fruit. 
It was called snerle (bindweed) in 1769-1848, rimpeurt in Thy (rimpe =sewing or stiching things); cat- or lamb guts, because the stems are tough; wild buckwheat in Jutland; jordhumle ( earth hop); skrædder (tailor),stenhvede (stone wheat), etc. etc.

Polygonum lapathifolium
Danish: Bleg pileurt
English: Curlytop Knotweed, Dockleaf Smartweed, Pale Persicaria, Pale Smartweed.

It is common in DK and it was once a very damaging weed upon moist lowland, it is similar to Polygonum persicaria, but it has glands on the underside of the leaves and on the flower stalks, and it has pale green flowers.

Polygonum amphibium
Danish: Vand-pileurt
English: Amphibious Bistort, Water Smartweed, Willow Grass. 

Amphibious bistort, lake in Hanstholm reserve
It grows in lakes and ponds, by wet ditches, but also upon halfdry -moist soil (amphibian soil). The pretty rose-red flower spikes are projecting above the water.
It was called rødgrøde, rødben which mean:  red porridge and redlegs. It had names like karruseblad (karusse = crucian, carp); hugormekål (viper cabbage), which was said in a derogatory meaning; hundetunge (dog's tongue) in Jutland, according to a game where people "licked" each other in the face with the wet leaves. - On the Faroe islands it was called kladur = scabies.

Polygonum hydropiper 
Danish: Bidende pileurt
English: Water Pepper, Common Smartweed, Marshpepper Smartweed.

It has white-green, red tainted  flowers in a thin, nodding spike. It grows in moist places, especially in woods. It was called Vandpeber (water pepper) in 1532, the whole plant has got a sharp pepper-taste. It was also called Edderblad (poison leaf).

Polygonum bistorta 
Danish: Slangeurt
English: Bistort , Common Bistort.

Its name was Slangerod in 1688-1848 (Snake root) and Øgleurt (Lizard herb) in 1810, the leaves are egg-shaped with a heart-shaped base, the inflorescence is formed like a roller, the long curvy root stock might look like a snake, therefore the plant was used against snake bites. It was cultivated as a medicinal plant in the gardens, and now as an ornamental plant.

Polygonum cuspidatum
Danish: Japan-pileurt
English: Crimson beauty, Donkey rhubarb, Hu zang, Japanese knotweed, Peashooter plant.

It is a garden-perennial from Japan. Its 2-3 meter high stiff stem has egg-shaped leaves and off-white inflorescence, it is often growing wild.
It was called Herregårdsbambus (Manor bamboo) Kæmpeboghvede (Giant buckwheat, American buckwheat and Turkish buckwheat).  
Polygonum baldschuanicum 
Danish: Sølvregn
English: Russian vine, Bukhara fleeceflower, Chinese fleecevine, "mile-a-minute",  Silver lace vine.

Russian vine

A very tall, until 15 meter twining shrub, which very quicly covers pergolas, wallwork etc. Numerous white and reddish flowers. The Danish nickname is still "arkitektens trøst" ( the architect's consolation ); old name pergola-sne (pergola snow).

Nors Lake, Thy

Seeds from the Common knot grass and the Curlytop knotweed were found in culture layers from Bronze and Iron Age.The Black bindweed was a weed in the earliest corn fields, numerous imprints of its fruits are seen in clay pots in settlements from late Stone Age, from the Great Migrations and from Bronze Age and later, but the only large collected find was made in 1949 upon a heath at Gørding by Nissum fjord (West Jutland): an ab. 1 liter vessel with handle contained 95 cm3 kernels, of which two thirds were rye, the rest were fruits from especially Black bindweed, Curlytop knotweed, Common pigweed and Corn Spurrey.  Many seeds from Curlytop knotweed were in the Egtvedgirl's from early Bronze Age. In claypot pieces from Celtic Iron Age were 238 imprints of its fruits. In a house site  from early Roman Iron Age ( near Ringkøbing  )were among pieces of a vessel found ab. 1 liter seeds. The fruits of the Polygonum, both in the stomach of the Tollund man and the Borremose man from early Iron Age, prove that these seeds of a weed were gathered for food.

The Black bindweed was in 1800 described as having seeds, which was just as nourishing and welltasting as the buckwheat.  Seeds from Black bindweed, Sheep's sorrel and Corn spurrey were baked into rye-bread. The root of Bistort can be grounded into flour for baking bread, and the leaves were used as salad.

The seeds, which were cleaned from the corn, were crushed for fodder for pigs and chicken.

Folk Medicine:

Lake with Polygonum in Hanstholm Reserve

NB: Blodurt (Blood herb) might also be Tormentil or Shepherd's purse in herbal books - and Slangeurt (Bistort) might be Slangerod (Birthwort)

Christiern Pedersen 1533:  decoction or juice from Common knot grass to drink against hemorrhage; the same to put on the genitals against bladder stones; the herb to use as a styptic compress upon wounds; if the herb is held in the hand it can stop nosebleed. Against too strong menses must goatshit mixed with the juice from blood herb be put upon genitals; women in childbirth should drink water extraction from pulverized blood herb.
Henrik Smid 1500s: the Common knot grass was very much praised by "The Old", and it was used to heal or ease a lot of sickness: decoction of red wine or destilled water from the seeds could stop all the flux from the stomach, and stop nausea, blood spitting, too strong menses, it drove out gouts, gravel and bladder stones, eased the inside heat from cholera, healed internal injuries. The juice or destilled water to drink or as a compress could stop all kinds of heat; to pour it into the ears against pain; to use it for bathing of "the evil and bad flesh"; it healed all wounds, especially on the genitals of both sexes.
Simon Paulli 1648: the juice from Common knot grass stops nose bleed, but it was said to be enough to hold the plant in the hand until it was warm; it heals blodsot (this might be dysentery) ; destilled water from or decoction of the plant and its juice to drink against bloody vomitting. The juice to be put as a compress on the woman's genitals against too strong menses. - The Bistort:  the roots might be used in the same way as the thick rootstock of Tormentil, the dried and crushed root was given in destilled water from the plant for blodflow in times ot the plague. Decoction for mouthwash of swollen gums and loose teeth. The root boiled in red wine and crushed, used as a compress upon loins and genitals, if an abortion was feared.

Folk Medicine (from various Polygonum):
Decoction from Heartweed to drink against constipation; the juice from Common knot grass against diarrhea; decoction or powder from Bistort against malaria and diarrhea. There are bladder stones in the body, if a decoction or juice from Common knot grass hurts, when they are put on the genitals. A tea from the plant was still drunk against bladder stones in the 1600s. Extraction from the root of the Amphibious bistort was used against gonorrhea and other venereal diseases. The juice from Common knot grass poured in the ear against boils or bloody excretia.

The root from Amphibious bistort is distributing and dissolving; the Heartweed belongs to the blood purifying plants; the juice from Common knot grass mixed with wine is styptic, both in and outside. Leaves and juice from Common knot grass and Heartweed heal eczema and wounds and drive out maggots in the wound. The juice can be rubbed upon cut wounds.  -   And it was said in 1761 that  "since it is growing in front of the farmer's door it can easily be found in a hurry".  Water decoction from Bistort was used for gurgling against "rottenness in the mouth", swollen and smelling gums and against toothache. In a magical tooth advice leaves of the Water pepper dipped in running water should be put on the tooth and then to be buried or rotten in a midden.

Vej-pileurt (Common knot grass) and the root of Slangeurt (Bistort) were written in the pharmacopoeia in 1772. Vej-pileurt was still sold in Danish pharmacies in 1979.

Medicine for the Livestock
Beer decoction from Common knot grass was given the cattle against diarrhea. The plant is mentioned among the plants, which are given to the cows on Valborg's aften 30/4 (Walpurgis Night) as a protection against witchcraft.
"Veteranians, quacks, and court-smiths" put leaves of Heartweed or Amphibious bistort upon the old wounds and boils of the horse. (in 1648). If the blood does not stop after a blood letting, the horse has to eat Common knot grass. (ab. 1730). The Amphibious bistort was used as a compress on the elbow- fungal infection of the horse; decoction of the Bistort was used against blooded urine. Upon a leg fracture of the horse was put on crushed Heartweed, and thereafter the plant had to rotten in a midden.
The Common knot grass was considered dangerous to the sheep, they got constipation and liver disease from eating it. 

Dyeing and other use
Crushed leaves from Heartweed dye yarn in a clear light yellow or green; Water pepper with the flower spike gives cloth an olive dye, and the root from Bistort is in general a fine black dye.
Upon the Faroe Islands the Heartweed and the Water pepper were used for dyeing wool yellow.

It was said the Water pepper could drive away fleas; the root of Bistort was used in tanneries.
Children playing used a special pretty specimen of the Heartweed for decoration.

The Heartweed  grew under the cross of Christ; the brown spots on the leaves came from his dripping blood.

Source: V J. Brøndegaard, Folk og Flora, bd.2, Dansk Etnobotanik, Rosenkilde og Bagger, 1979. 
photo in North Jutland 2007-2008: grethe bachman, (except Common knot grass, loan from wikipedia)

Amphibious bistort, Nors lake, Thy

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