Many years ago in ignorance I planted one of these in my garden. It said"clump forming" on the label but missed out crucial piece of information that the clumps were indefinite spread. So for 20 years we have battled to contain it but now it has to go as it has cracked a retaining wall. I have noticed that this year it is flowering and a vague memory that bamboo dies after flowering but I have a feeling that's not going to be the case. Roundup doesn't touch so is there something on the market that will kill it?