|Japanese knotweed, 2010. Edible up to this stage.|
The plant is extremely invasive; it will overrun any of our native plants; cutting it doesn't kill it, nor does digging it out. An inch of root or stem left behind will sprout again. The roots spread up to 20 metres, and can break through pavement. The only thing that halfway seems to work is cutting it over and over and over ... It still comes back; I've been cutting ours for 3 years now, but at least it's not quite so enthusiastic, and it hasn't spread.
I think that if more people knew how good it is to eat and how much of a healthfood it seems to be (see reservatrol), it might have a bit less chance of taking over. So here's my recipe:
Cut knotweed sprouts before the leaves have opened completely. A knife helps, but I've been able to snap them off or even pull them up with a bit of root with my hands. Bring in all the cut pieces; do not leave any lying on the ground to root again.
Stems may be from pencil-thin to about 1/2 inch across. After this, they are tough and fibrous. Wash them, then cut them in 1-inch pieces. I usually cut out the "knots", but if the stalk is tender, this is not necessary. If the stem resists your knife, discard it; it will be mainly fiber. Most of it will be crisp and juicy.
Boil the batch or microwave it for a few minutes, just until it turns to mush. It will look and taste like pale cooked rhubarb.
Add sugar or sugar substitute to taste. (Low carbers, use stevia or something similar. This makes an excellent low-carb "fruit".)
Use in any rhubarb recipe. I like to mix it, chilled, into strawberry jelly, or cook it half and half with rhubarb, for added colour. Without the sugar, it makes a good sauce for pork.
Throw any discarded pieces in the trash, or dry and incinerate. DO NOT COMPOST; THEY WILL SPROUT!