Originally Posted by ron_mcb
ok i got the 24 inch barricade to be safe. you really dont think they would go any deeper if the roots are not packed and its kept trimmed? if annual trimming is done it would help control the growth, did you mean just thinning out canes near the barrier or randomly removing a few canes from the center of your plot?
Basically digging a trench around the bamboo, maybe 8 inches deep should be able to catch any rhizomes that cross by, and severing them is enough to make the disconnected section rot since they are no longer connected to a source of energy (culms). You can thin culms in the center if there are too many however annual rhizome pruning after the rhizomes are done growing in the fall can ensure that no shoots come out of the area that you plan on containing it.
I'm not sure about how far they can run in a single season in warmer climates, but annual rhizome pruning can keep them controlled no matter how far they run.
Here's a picture that shows how my running bamboos grow. I've never had to rhizome prune yet, but bamboo rhizomes obviously require warmth in order to run which means that many running species don't run around here.