State Noxious: AL (CCW), CA (BW), CT (IB), MA (P), NH (PIS), OR (BDW, Q), WA (CBW, NWSPQ)
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Scientific Name:Polygonum Cuspidatum
Common Name(s): Japanese Knotweed
Parts Used: stem
oneraindog 28 May, 2009
Large perennial herb to 10 ft high often forming dense colonies. Stems are upright with a hollow core, smooth, mottled with light brown spots and frequent branchings. Leaves alternate, simple, 4-6 inches long, 2-5 inches wide, broadest near the base, long tipped, wavy along the margins, squared to rounded at the base with a somewhat leathery texture. The jointed leafstalk is stout and sturdy, enclosed at base by membranous sheath that also surrounds the stem.
Flowers produced in elongate, branched clusters in junctions of upper leaves. Each flower is tiny 1-2mm long, white.
Japanese knotweed grows on disturbed soil, along roadsides and riverbanks, in other moist areas, and in fields
Locate papery, dry, woody stalks of the previous year. Gather young shoots up to 1 ft for pot herb, up to 3 ft for other uses.
Boil tips of young shoots in saltwater. serve like asparagus. peel older stalks and use like rhubarb. Slice the stems, steam as a vegetable, and simmer in soups, sauces, fruit compotes, and jam, or bake in dessert dishes
The plant is an excellent source of resveratol, a substance known to lower LDL (bad) cholesterol, reducing the risk of heart attacks. Resveratol has been claimed to delay the onset of Alzheimer's or slow its progression. Also good source for
vitamin A, along with vitamin C and its cofactor, the antioxidant flavonoid rutin. also provides potassium, phosphorus, zinc, and manganese
Large quantities of Japanese knotweed will act as a laxative.