I agree with Glaucus. In the upper Midwest, I have found it useful when working with landscape-type azaleas, to pay attention to the solar calendar. For example, I try to get repotting done before the Vernal Equinox, and hard-prune no later than the summer solstice. I’m still experimenting with this, and there are always exceptional situations like emergency re-pots, but my rationale is that repotting before the onset of spring allows plenty of growing season for the roots to recover. It seems that if I hard-prune any later, the new growth will form few if any flower buds by fall. For my deciduous azaleas, I wait until the Autumnal equinox to do branch cutback for ramification in the following spring.
in my experience, if you have freeze-induced bark separation there is little likelihood of that trunk surviving, and worse, you’ll get dieback all the way into the related portion of the root mass. I have not had this problem since I went to using a small greenhouse kept at 37 degrees—cold enough for dormancy, but warm enough to prevent cold injury.