I'm thinking about buying my mom a couple small fruit trees to go on either side of her patio. They aren't big planters, maybe about 3 by 3 1/2 feet. They've got an open bottom and two 'open' sides. The other two sides are concrete patio. I'm going to go down to home depot in a few minutes to see what's available (looked at walmart, but wasn't impressed, next try is the local nursery). If I buy a couple trees, how to I make sure that they'll stay small? I'd like to keep them patio sized, but still be able to get some fruit off of them once they're more mature. I also want to make sure that they don't grow so big that they break up the concrete patio, brush up against the house, or get taller than the patio's roof.