Bamboo's can be very hard to kill. Tillandsia is correct. But I am not sure if you should cut it back all the way to the ground. Spray it with Roundup to kill it (the roots must die before you dig it up. Contact the garden's family gardening center. They have experts there that can tell you how to deal with any lawn/garden problem.
Either by digging it out (some stolen are left behind and the plant will come back) or cutting it back and spraying roundup then digging it up.
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