Marsha, your thinking-out-loud is sound. "Should I return it to my mostly shady back yard?"
I have a 6 year old Braeburn
apple tree the deer had completely defoliated when it was "2" (snuck their head under its chicken-wire fence!). I figured it was a goner... But I made the effort to shade it from the midday sun (with an ugly blue tarp over the steel fence posts), watered it well (in it's permanent clay home), and it grew another set of leaves - and survived - in midsummer!
I'd set "Ashmead" where it receives morning, and partial midday sun; if it rejuvenates itself, "inch it" back into full sun. As I've been moaning lately ... it's a great
year for disease! Let's hope some sunshine does everything / one some good.
Is your crab apple trapped in clay too? If so, save the transplanting for January!
Most rootstock is bred for its ability to handle various soils; i.e. clay. But I think you're always better off potting with as rich and well-draining blend of soil as you can afford
. Due to the constriction of a pot, trees need all the nutrients they can get before being set out - anywhere. Every potted nursery tree I've bought has had that "rich" treatment; and once they arrive here in Clayville
- they've done as well as could be expected.
PS; Hi to my Friends in Southeast!
(Marysville & Marshall)