Chapters 6.34
6.34 - of Alpine Knotweed (Polygonum phytolaccaefolium)
Jonathan Sawicki , University of Guelph, Canada
Suggested citation for this chapter.
Sawicki,J. (2022) Greens, Fleshy Stems and Gourds. In The Student Encyclopedia of Canadian Indigenous Foods. Editor, M.N. Raizada, University of Guelph, Canada. http://www.firstnationsfoods.org/
Introduction
Alpine knotweed (Polygonum phytolaccaefolium)a species of plant in the knotweed family and is commonly known as wild rhubarb. This plant has been eaten by the indigenous peoples of Northern Canada and Alaska for a significant amount of time. Alpine Knotweed is high in vitamin C, Calcium and vitamin A. This paper aims to educate Canadians on Alpine Knotweed, its anatomy, and the potential future market for Canadians.
Plant Information
Alpine knotweed or “wild Rhubarb” (Polygonum phytolaccaefolium; Polygonum Alaskanum and Polygonum alpinum) is a plant in the Polygonum genus within the knotweed or Polygonaceae family (Kuhnlein & Turner 1991). Other species in the Polygonum genus include Mountain Bistort (Polygonum bistorta), Smokeweed Bistort (P. bistortoides), Smartweed (P. hydropiper), and Alpine Bistort (P. viviparum). This paper will focus on Alpine Knotweed and will use the other species to support and fill gaps where information on Alpine Knotweed is insufficient.
Alpine knotweed is a free-branching perennial herb, it forms from a strong rootstock that can be several inches thick (Porsild, 1953). The stems are leafy and may reach three to six feet tall (Porsild, 1953). As the stems thicken, they become a reddish colour at the joints where the 5 cm – 20 cm leaves rise from (Porsild, 1953). The leaves are narrow and oval tapering at the end to a point (Kuhnlein & Turner 1991). The flowers are small off-white to greenish in colour, in thin, many-numbered bunches at the end of the stems (Kuhnlein & Turner 1991). Figure 1 shows the phenological development of a Polygonum genus species.
Geographical Origins
The plant's native North American range includes Alaska, the Yukon and the Northwest Territories (USDA, 2022). Alpine Knotweed is also found in eastern Asia and its range extends eastward to the Mackenzie River and travels northward slightly beyond the tree line (Porsild, 1953). It can also be found in Montana, Idaho, Nevada, and Northern California and is presumed to grow in the mountains of British Columbia (Kuhnlein & Turner 1991). Alpine Knotweed is a very adaptable plant but prefers moist open soils that regularly occur on the edges of riverbanks and mountain landslides (Posild, 1953). The other species have a much larger native range than that of Alpine Knotweed (USDA, 2022) as seen in figures three and four,
Alpine Knotweed performs better in the medium to lower elevation ranges and on moderately steep slopes, with an average slope of 13 degrees (Denali National Park and Preserve, 2022)
Consumption
Alpine Knotweed is used in many ways. Before consumption, the plant must be harvested. Harvesting is best done when the plants are 4 to 10 inches high and before the plant flowers (Jones, 1983) Though the size of the plant is important the most vital component to a tasty plant is the juiciness/tenderness. Some plants that are growing in shady damp areas will be juicy and tender even though they may be 18 inches tall and have a stalk that is 1 inch in diameter (Jones, 1983). The best time of the year to pick Alpine Knotweed is usually in the late spring or early summer depending on latitude (Jones, 1983). Known as Alaskan Wild Rhubarb, the plant stems are eaten when they are bright red and roughly the size of a finger (Posild, 1953). These conditions appear soon after the snow melts and as the name suggests, they are treated like domestic rhubarb (Posild, 1953). The plant can be eaten raw, usually dipped in seal oil and is often blanched or boiled (Jones 1983). The cooked plants are often mixed with meat or fish and can be stored for a few days, this dish is known as tinjutchialik (Jones, 1983). Young plants are cut up and eaten fresh with meat or fish by the Inupiaq Inuit of Alaska ((Kuhnlein & Turner
1991). Alpine Knotweed juice also provides a refreshing beverage (Posild, 1953). Furthermore, the native Canadians of the Upper Yukon River make a dish with sugar, flour and water and then add the early plants' cut leaves and stems (Kuhnlein & Turner 1991).
Nutrition
One cup of Alaskan wild rhubarb contains roughly 10% of recommended daily fibre, 44% of vitamin C, 20% of calcium, and 72% of vitamin A (Jones, 1983). Because of the high vitamin C content, Alpine Knotweed has been traditionally used by the Dena’ina people to treat coughs and colds (Kari 1985). Vitamins C and A as well as fibre are vital nutritional components of a person’s diet.
Storage
Alpine Knotweed must be stored as cool as possible. Usually, barrels of the plant are buried underground, covered in moss and eventually taken out pre-freeze, cleaned of mould and consumed (Jones, 1983) The barrels stored underground will ferment and develop different flavours according to the temperature it is stored (Jones, 1983). Alpine Knotweed keeps very well if it is able to be frozen, but the flavour and texture will not be as good as before it was frozen (Jones, 1983).
Associated Indigenous Peoples
Because Alpine Knotweed’s native range is in the far north of Canada and Alaska the indigenous tribes who used the plant as a source of food include the Inuit, Kutchin and Loucheux tribes and others, Alaskan tribes including the Dena’ina used Alpine Knotweed as well (Jones, 1983). Figure 6 shows some of the distribution of indigenous tribes in Northern Canada that utilized Alpine Knotweed as a food and nutrient source. Other plants in the polygonum genus such as sour dock provide more nutrition than Alpine Knotweed, but it was still a commonly used plant because it was easy to harvest and available in large quantities (Jones, 1983).
Limitations
Many plants in the polygonum family contain levels of oxalic acid, this gives the plant a palatable sour flavour (Kuhnlein & Turner 1991). If eaten in large amounts, oxalic acid can lead to the build-up of oxalate crystals in the organs and can lead to kidney stones (Hodgkinson & Zarembski, 1968). Alpine knotweed currently grows wild, usually in the far north of Alaska and the Yukon. This can make it difficult to harvest and cultivate. As the climate continues to warm the effects it will have on the growth of Alpine Knotweed is unknown. In cities and many urban
areas plants in the polygonum genus are considered weeds (OMAFRA, 2022). Alpine Knotweed is closely related to the well-known and hardy plant Rhubarb which is already grown in great quantities. Therefore, turning Alpine knotweed into an agricultural commodity would be a difficult task.
Alpine Knotweed provides indigenous peoples of Northern Canada and Alaska with a source of food that contains fibre, vitamins A and C. It grows well on riverbanks and mountainsides and can be stored for a long time. Other foods have higher nutrient values but do not grow in large quantities compared to Alpine Knotweed. Alaskan Wild Rhubarb has been used for many years. Education must expand and continue to keep the knowledge of the plant as important food source,
References
1.Hageman, A., & Galoustian, P. (2020). In Economic aspects of the indigenous experience in Canada. Kingston, ON: Queen's University.
2.Hodgkinson, A., & Zarembski, P. M. (1968). Oxalic acid metabolism in man: A Review. Calcified Tissue Research, 2(1), 115–132. https://doi.org/10.1007/bf02279201
3.Kuhnlein, H, V. Turner, N, J. (1991) Traditional Plant Foods Of Canadian Indigenous Peoples Nutrition, Botany And Use. Gordon And Breach Publishers https://www.fao.org/3/ai215e/ai215e.pdf
4.Jones, A. (1983). Polygonum Alaskanum. In Nauriat Niginaqtuat: Plants that we eat (pp. 45-51). Maniilaq Association.
5.Ministry of Agriculture, Food and Rural Affairs. Smartweed, Swamp (Polygonum coccineum Muhl.). http://omafra.gov.on.ca/english/crops/field/weeds/swamp_smartweed.htm
6.Porsild, A. E. (1953) Edible plants of the Arctic. Arctic 6 (1): 15-34
7.Polygonum Alpinum. USDA plants database. https://plants.usda.gov/home/plantProfile?symbol=POAL11