Japanese knotweed
By Adamski
United Kingdom 
I have recently built a 1 metre cubed compost heap which seems to be doing really well, lots of worms, bugs and warmth. But I now realise that I have included a few stems of what I think is Japanese knotweed. It was completely shredded first but is this likely to rot and not regrow or to cause me problems if I use the compost. Thanks
26 Aug, 2008
Answers
By all means keep a watch out for sprouts of JK but I would also give in and keep the chemical killer nearby. It really is the only way to get rid of this biological monster -- zap the new shoots as they appear and keep on doing it year after year after year (three years should see it dead but don't count on it!)
27 Aug, 2008
Previous question
Japanese Knotweed grows back if there's even a very small piece of root left in the ground, so I would be a bit worried about this. I think it might be best to turn the compost more than you usually would, if you can, and watch out for anything suspicious like small pink shoots growing. Or, if possible, after a few months, turn the whole lot out onto a tarpaulin and rake through it for signs of growth. I do hope that it just rots down, as you have shredded it, but having had J.K in my previous garden, I know its wicked tricks! Good luck!
26 Aug, 2008