Um, I would think again about bamboo, clumping or spreading. One of my friends have the giant (clumping) one that was behaving itself along the fenceline behind their vegie garden. For some reason, it suddenly decided that it want to take over and they are finding shoots up to 20 feet away. If you have a small island you could grow it on, you might find you never have to worry about it turning up where you really dont want it.