this is a sort of bamboo which is not making such a mess with rhizome. ( site shoots ) when i remember right it is a "gelber bambus" phyllostachys aureosulcata. growing fast and high but not so much into a high range."what did you give them to grow that fast"? Laka-poo?
What do you do to "contain" them? Your fresh shoots seem to "shoot" from the center, not from the sides?
guess it was nearly 3,5m high this year but not looking good anymore because there where a lot of dead stem and it was not growing good like the years before. so i deciced to cut them totally down and as you can see its getting light and more water now and is growing as fuck again lol