Japanese Knotweed,  Reynoutria japonica, Is a common invasive plant found in many parts of the world. The roots of this plant are extremely high in resveratrol and are medicinal. The young shoots are a great substitute for rhubarb, and they can be pickled, made into sauces, cooked as a vegetable, and enjoyed many other ways. Forager Chef has an awesome article here about most of the good uses and full preparation details.

As always we only harvest from clean areas. Since Japanese Knotweed is an invasive plant, overharvesting is not a concern. A real concern though, would be how you dispose of your unused knotweed. Do not put these in your compost pile! they are invasive and can spread like bamboo, and you definitely do not want this plant propagating on your property as it is very hard to control, like bamboo.