Giant Knotweed, Polygonum sachalinense (Fallopia sachalinensis) is similarly consume except its fruit is eaten as well, or stored in oil.
No references are given as to how to cook them nor have I tried. Tsk…Tsk… The California Department of Food and Agriculture and the book Cornucopia II both say the rhizomes are edible. For the health conscious it is a major source of resveratrol and Vitamin C … a noxious weed AND very healthy. Many folks say it tastes like rhubarb but I think a lemony green is more accurate, crunchy and tender.
Forages take advantage of it eating - raw or cooked - young shoots, growing tips of larger plants and unfurled leaves on the stalk and branches. Knotweed, in the Buckwheat family, is not liked in western nations because it grows around three feet a month, sends roots down some 10 feet, grows through concrete, damaging roads, dams, buildings and just about anything made by man.
What do they know the rest of the world doesn’t? It is said that Japanese Knotweed out lives the gardener and the garden. About the only place where they are not upset with the plant is where it’s native, southeast Asia. It’s an invasive weed in Ohio, Vermont, West Virginia, New York, Alaska, Pennsylvania, Oregon and Washington. It arrived in North America in the late 180os and is officially found in 39 of the 50 United States, probably more, and six provinces of Canada. Japanese Knotweed is also “invading” New Zealand, Australia, and Tasmania. It increased the construction cost of the 2012 Olympic stadium by some 70 million pounds. In fact they spend some two billion pounds to combat it annually, which as of this writing is about three billion dollars a year. Introduced into Great Britain by 1825 Japanese Knotweed has been on the decimation list for more than 30 years and has to be disposed at landfills licensed to handle the dreaded edible. Perhaps it should be planted in countries where starvation is annual. Japanese Knotweed is listed by the World Conservation Union as one of the world’s worst invasive species.