Seeing any dieback on your trees yet? Only one I have noticed is a mulberry I propogating. Everything I have is at least zone 4 at my zone 5/6 home. Even granny Smith which is at least group 5 due to long time to ripe, that's been good.
At camp looks like -18 has been the coldest recorded where there's a weather station. Usually at camp it's another 4 or 5 degrees colder when it's bad out.
Any nurseries bite on clowns nose yet?