Hi pixiebee; I imagine Charles is a bit busy to reply right now, (I`m sure he will). The absence of any other replies is probably because nobody likes to mention the `K` word in case it invokes the monster into appearing 
Sorry but it really is a serious problem. Are you sure it is j.k? Apart from fastidiously cutting off all growth as soon as it appears I`m not sure if there is an organic solution. Have you any idea where it came from because if its in a neighbouring garden, it will always re-occur.
Cheers
Pete 