Japanese Knotweed is from the rhubarb family, I wonder if that would also work?
I will give it a go - a great use for the stuff & we have no shortage here!
P.S. Just as a matter of interested knotweed tastes just like rhubarb and you can harvest the young shoots as they come up, once over 8-9" they become tough so you do need to harvest young.
I'd be too terrified to eat Japanese Knotweed. All that talk about it growing through concrete, coming through walls of new build houses - I'd be scared it'd grow inside me!!