Bus- Sounds good. I'll snap a picture and upload it later tonight. The maples I have are roughly 30-36" and are just shooting out their leaves (perfect for shipping right now). I have yet to trade (new) so maybe you can guide me along here. Yes they have been rooted by me and require the ideal conditions and climate (my personal experience).

I for one am not an advocate of bare rooting Japanese maples at any time other than when fully dormant. Their roots are extremely sensitive to disturbance and the trauma of bare rooting, shipping and replanting at this time of the season is sufficient to send any JM into shock. My preference would have been to pot it up and baby it for awhile before planting out in the ground in full-on sun, specially in mid June. My nursery advocates extreme care when planting even well-established containerized or B&B maples at this time of year and our summers are notoriously late to start and NOT hot when they do arrive, if rather dry. I think David's advice is sound. Without seeing your soil and planting conditions firsthand, it is only speculation but the amending you have done in "heavy clay" soil may be creating a poor drainage situation - too much moisture remaining in close contact with the roots and not percolating down through the soil level. Generally, if working with a heavy soil it is recommended to dig a very wide but shallow planting hole adding no amendments. Plant the tree high, backfill with the soil you removed and add the amendments as a mulch to smooth out to the top of the roots. This wide, dished planting hole will allow for adequate drainage without creating a bathtub effect of a deeper, amended hole. Personally, after such a short period of time in the ground, I'd be inclined to lift the tree and pot up into a container where you are able to more closely monitor the amount of sun and water it will receive and give some much needed TLC. Forget the fertilizer - stressed plants are unable to metabolize much anyway. And you can add me to the list of those who think that SuperThrive (or SuperJive, as a friend refers to it) is pretty much just very well-marketed snake oil. The active ingredient (primarily B1) is present in such an infinitesimal amount and then is further diluted by water that it is providing virtually no measurable benefit to the plant.

The usual term is cuttings rather than rootings, you should find much more searching with the customary word. With cuttings of deciduous trees and shrubs it is often necessary to follow a comparatively strict procedure in order to get them to both form roots and then grow away again the following spring. If the tips of the rooted cuttings do not have time to flush a new stem growth, form overwintering terminal bud the cuttings may fail to continue growing the following spring - despite having had roots and remained alive up to that point. To overcome this more difficult kinds are taken as early as possible in the growing season, put under mist to keep them from shriveling before the roots form. But if you are getting some new top growth from at least the one cutting this may not be your problem - at least with the one cutting. If it did not form very many roots there may not be enough of a root system yet to support a full top growth. Or there could be some other problem or limitation present, it sounds like it may have died back a bit. Yes: amending of individual planting holes with organic material when setting out long-term plants like trees and shrubs is counterproductive, due to how it affects movement of water into and out of the amended planting hole.

In zone 5, and those were my trees, I might slip the seedlings out of their china-pot and into something frost-able. Like a tupperware pot with drains. In four to eight weeks as it gets cold at night I would want something to serve as a cloche. it will need to come off in the morning and be covered at sunset. Eventually the soil will freeze and the cloche can stay in place will March or so. The deal here isn't to protect it from freezing but from too many freeze-thaw cycles. If you go to where ever you collected those wings from, seedlings there got nothin' for protection. Yours will not prosper for the protection. The cloche is to keep cold-cold, and reduce damage from compacting snow-ice.