You probably grafted too soon as you rootstock was not ready. You should have kept the scions refrigerated until the rootstock showed it was coming out of dormancy. What you have now I would keep in partial shade for this summer. Are you planning on planting it in the ground? If so I would wait until the weather cools and plant it in the full sun. If you intend it to be grown only as a container tree, I would rethink your soil choice for a long life container mix. Al

You could plant it now, if not, bury the pot a little in the fall.
Don't over fertilize and water late in season, best a little on the dry side, [late September] so the new growth can harden up a bit. Protect against vole damage.

Thank you for the ideas. I am planning on keeping it in the pot and burying it in the ground this fall, then planting it in a place secure from bears and deer in spring when we can put up a good sturdy fence for a garden.

I actually did have the scions in the root cellar, which is fridge temperature, until the rootstock started budding. It was colder than usual in Idaho, so it was late when I grafted. I don't know why the one stayed alive when it didn't leaf out, but now it has leaves, so I am hopeful it will become a healthy tree.

I will keep it in partial shade for the summer, and slow the fertilizer and water in fall before planting. I am so excited to have a possible tree from the one I left in Washington. That tree had the best apples EVER!

: )