Thanks folks, after a quick google it looks like I can harvest this for my compost heap :)
Any other uses for it?
It has spread quite a lot so I am guessing it is not the sterile version mentioned on wikipedia. Been back down and there is about half a footy field worth of it so if you can think of any uses for it i'd be all ears :)
Looks very pretty, I think I will wait till it finishes flowering before taking any.