Dacotahrose, that sounds like enough room for one to spread out and make a lovely specimen tree, but maybe not for two. You could try to make a double-tree clump out of them, by planting them close together in the same hole. That way, you would have the other if one got damaged or died, and it would be prettier, in my opinion, that trying to both give the trees (not enough) room and squeeze the two of them into the sheltered spot. See how they do over the summer, and then plan to make some sort of shelter for them in the late fall. How and what you do will depend somewhat on how big the trees have grown over the summer. Come back then and ask, and I am sure you will get plenty of advice. Even with winter protection, they may not make it, which is why I suggested earlier that you contact the company and try to get something more suitable. Purely out of curiousity, would you be willing to share the name of the company your relative bought them from? If they were really resposible, and not a phone room in one state, nursery in another state, with people hired who can do little more than answer the phone and push buttons on a computer, they SHOULD have said something to your relative about the zones. Of course, your relative may have insisted on these and only these, also....

one way to keep them moist is cover the pots with plastic bags and poke a little hole in the bag. No they are not slow growers. You can get two Ft plants in 8-9 months. Put them under fluorescent lights

JL Hudson Seed has Oxydendrum. He has a website, most seed packages are $1.50 -

Among my very favorite trees. Be aware that these are quite slow growing (which can translate into expensive when you go to buy one). Also, they resent disturbance of the root zone. As g-gal mentioned, these are one of the most reliable & dramatic trees for fall color, and, in fact, are beautiful year-round. There are some nice old specimens in the Washington Park Aboretum, which prove that these will become quite large, but only after many years. Plant one...or two - you won't regret it!