I came in to say bamboo too. There are many varieties that don’t spread like mad. They don’t flower (at least, not often) but they’re very relaxing to look at and listen to. And I just learned from this article that “Bamboo sequesters carbon dioxide at far higher rates than an equivalent stand of trees and releases up to three times the amount of oxygen.” and their hairy leaves are good for removing all that road dirt out of the air too.
Now I want some bamboo.