Any thoughts?

I have a unique challenge. Our neighbors just built an office on top of his detached garage. The windows of his new office look out directly on our backyard and pool. There is currently a 6 ft stone/brick fence separating the properties. We would like to put up a hedge or tree privacy screen along the fence line. The hedges/trees would need to stand 10 - 15 ft +/-. The problem is, the distance from our pool to the stone fence is only about 10ft and is all concrete; so any hedge or tree planted would need to go in a planter of some kind.

Any thoughts on a tree or hedge that could grow to the height we would like, and survive in an above ground planter?

Thanks much.