AMPHIBIOUS PERSICARIA, WATER SMARTWEED, POLYGONUM AMPHIBIUM OR PERSICARIA AMPHIBIAAmphibia persicaria is also known as Water Smartweed, Amphibious knotweed, and Amphibious bistort. It is a flowering plant in the knotweed family of Polygonaceae, and can grow in water as much as 8 feet deep, although it is found in much shallower water normally. The thick stems grow from the plant’s rhizomes and it has a cluster of pink flowers at the top of the stem (sometimes these grow to 3 metres long), which are 5 lobed and pointed. It flowers in the months of July and August, and then produces small, shiny, brown seeds.
Native Americans used to eat the young shoots as a relish, and used it in medicine and as hunting medicine. They would use the flower heads as bait when trout fishing and the smoke from the leaves of the plant was thought to attract deer to hunters. A poultice of freshly gathered roots was used on mouth ulcers, and an infusion of the dried roots was given as a remedy for chest colds. Interestingly, Dioscorides, in 1 AD thought that the roots were useless. He attributed cooling and astringent properties to the plant and said that they were used in much the same ways as the persicaria that grows in fields. He used the plants as a diuretic, for excessive menstruation, to get rid of sores and their pus in ears, and boiled in wine for ulcers on the genitals. He put the leaves on fresh wounds, used them internally for burning sensations in the stomach and for herpes and other inflammations.
Amphibious persicaria is native to both Europe and Asia as well as to North America. In other countries it has been introduced and has, in some of these, become a noxious, invasive species, taking over ponds and lakes. It is related to the Water pepper, and should not be confused with it. (Polygonum hydropiper)
The Welsh physicians of Myddfai used it in remedies for fever, such as these two; -
“The mugwort, madder, meadow sweet, milfoil, hemp, red cabbage, and the tutsan, all these seven herbs enter into the composition of the medicine required. Whosoever obtains them all, will not languish long from a wounded lung, or need fear for his life. Any of the following herbs may be added thereto, butcher's broom, agrimony, tutsan, dwarf elder, amphibious persicaria, centaury, round birth wort, field scabious, pepper mint, daisy, knap weed, roots of the red nettle, crake berry, St. John's wort, privet, wood betony, the roots of the yellow goat's beard, heath, water avens, woodruff, leaves of the earth nut, agrimony, wormwood, the bastard balm, small burdock, and the orpine.”
“Another treatment for an intermittent fever: Take the mugwort, dwarf elder, tutsan, amphibious persicaria, pimpernel, butcher's broom, elder bark, and the mallow, and boiling them together as well as possible in a pot, or cauldron. Then take the water and herbs, and add them to the bath.”The following was used as a cure for stones or gravel in the kidneys: -
“If the disease be gravel, make a medicine of the following herbs, macerated in strong clear wheat ale, viz. water pimpernel, tutsan, meadow sweet, St. John's wort, ground ivy, agrimony, milfoil, birch, common burnet, columbine, motherwort, laurel, gromwel, betony, borage, dandelion, little field madder, amphibious persicaria, liverwort.”
