It's looked like a black bamboo to me. I started a black bamboo in my backyard last year. Mine is not as tall as yours.

The best way to deal with the uncontrolled bamboo problem is to mow down the shoots as they come in. As they are shooting, they are very soft and easy to cut down, you can even kick them over. Black bamboo will shoot April, May and June, with some wimpy shoots about a month on either side of it.

As for cutting down established and hardened off culms, good luck. You may use a sawzall and a chainsaw. They are both pretty effective, but the "fiberglass" nature of the plant will dull many blades.