I've also heard people complain that glyphosate does nothing. It depends on the the type of bamboo, some are real thugs, others more easily eradicated. Sasa spp are about as eradicable as bindweed.

The thing to realise is that they use a lot of energy from the rhizome when they shoot in the spring/early summer. Also, there is often some time elapsed between shooting the culm and putting the leaves out. Also they are storing a lot of energy in late summer and autumn. So you can tire them out by (1) cutting all the culms down now to stop them storing any more energy and (2) cutting down all next year's new culms when they are well extended but before they leaf out. Should eventually kill most of them off this way. You can try the glyphosate, but then you'll have to leave the culms up now when they are at their main storage phase.