beeman:

Franktank in Wisconsin is doing this so you might contact him or maybe he will see this. It can be done but is a lot more effort and the tree will need repotting after a few years. I water mine every day in summer.

I do this with all kinds of trees (My backyard looks like a nursery)...

You can plant them in the ground, but its just additional work, but if you are going for a "look" for your yard or whatever, then go ahead...you will most likely have roots growing out of the bottom of the pot by late summer, which will probably have some negative effect next year (too much top/not enough bottom?)... I'd use min 15 gallon pot. You can use whiskey barrels, but put them on wheels and be prepared for them to rot out in 5 years or so unless you line them with something.

Garage is fine. They'll do great. My pluots all look great...all 8 varieties.

One issue you may run into is height. I prefer short trees/low branching...i'm getting to the point i have to angle my trees into the garage (Garage door is only so tall)...

Winter treatment? I roll them in there and take them out in spring... roll them in and out of the frosts if you want. Maybe make sure they have a little moisture before setting them away for winter...

Have a decent dolly handy too...even 15 gallon plastic pots get heavy.