Bamboo still follows the one space rule that trees do. I read somewhere that you could plant it right next to other bamboo, but that has not been my experience, and I've planted a lot of bamboo.
Eventually, you'll still be knee deep in bamboo shoots, even if half of them die. And of course you can plant bushes right next to bamboo, and vice versa, just as long as there's adequate space (not on the edge of water or a cliff).
Haha. I bet they reproduce fast!
Of course when I want to put them around a bench, they don't fit correctly around... I'll have to figure something out.