Trees In A Planter Box
On top of my stone patio, I'd like to put in a 5' x 5' planter box that's 3' tall and I'd like plant a tree in there. Something like a cherry tree or crab apple or japanese maple or pear tree, etc. Something that's bare trunk for the first 6'-8', and then branches out at the top. Hoping for something around 15'-20' tall with a 10'-15' diameter at the top.
What trees similar to what I described would grow well in a planter box in Massachusetts (bearing in mind it will be kept outside all winter)?