Temporary Home for Grafted Apple Tree?
On Friday, my 11-year-old son brought home an apple tree that he grafted himself in his after-school gardening club. (How cool is that? I thought they'd be growing green beans in dixie cups. ;)) Needless to say, he's very pleased with it and wants to plant it in our yard. Unfortunately, we don't have a lot of space in which to grow a fruit tree, even one grafted onto dwarf stock. Our only option would be to grow it, along with a pollinator friend, in large containers. I'm going to email the teacher on Monday to find out exactly what rootstock was used, but my son said they were told the tree would grow to be 6' tall, so it sounds like it's a pretty dwarfing stock.
1) Since we're not ready to commit to two half-barrel size containers just yet, I'd like to plant it out into a smaller container to keep it alive while we figure out the logistics of whether we can keep it long-term. What size pot can I get away with? I have some 2 gallon black nursery pots ready to go, but would the roots get too hot in the sun? Would a white 5-gallon bucket (with drainage holes, etc.) from the home improvement store hold it through the summer? How long could it stay in a container like this until it had to be potted up?
2) If we do decide to keep it, what varieties would cross-pollinate with a Cox Orange Pippen? I've seen conflicting information online -- some websites call it self-fertile, while others call it self-sterile. Which is correct? Would any of the columnar apple varieties be a good future companion? We live in central Indiana, zone 5.
Thanks for your help,