I'm not sure I understand exactly what you did and how that impacted the trees. They were indoors, you took them out and then brought them back in?? Can you explain further? Under what conditions did you store them over winter?

They were outdoors and I brought them in about a month ago.

Why did you bring them in at all? They are hardy to zone 4-5, depending on variety, and even after starting to leaf out mine have been OK to 20F. If the leaves came while indoors and you put it outside without the hardening off process, many of the leaves will end up dying.

Yeh, the in and out thing has caused stress on the plants, most likely from too abrupt changes in temperature and the dryness of any indoor environment.

The good news is that the tree(s) will releaf. Just get them back outside under the proper conditions after an appropriate period of acclimation (hardening off).

With respect to hardiness and cold damage......not all cultivars of JM's are equally hardy and zone 5 is typically considered the lowest zone they will tolerate successfully. Sure, some folks do manage to get them to survive in z4 but it is not a given. Nor is it a given even in z5! That would be considered a borderline situation, given the possibility that 50% of winters could achieve cold temperatures below the listed zone minimum. The longer established in that sort of climate, the better able the tree is to withstand unusual winter cold.

And that hardiness rating has absolutely nothing to do with their tolerance for cold if container grown plants. Container JM's are far more likely to be killed at higher winter temps than are their inground planted brethren. That's because the roots are far more vulnerable to cold damage than is the woody topgrowth and exposure to ambient air temperatures (colder than the inground temps) surrounding the exposed containers below 25F for any extended period will kill them. Dead roots = dead plant. Also budded or newly emerging leaves are also easily damaged by late spring freezes. But these are recoverable.

Some new growth can look like it's wilted and sunburned even though it's not. A mistake new gardeners often make. Probably not this case, but I thought I'd bring it up.

I brought them in because i was impatient. lesson learnt. they don't like being thrown off schedule. i sent them back outside for the last week. now they are sort of stunted - frozen in mid leaf out. :( I did buy some happy frog fertilizer and will try that out on them maybe it will help.