rockm

I think this depends greatly on the species you're dealing with. I have alot of Southern U.S. natives-- Bald Cypress, live oak, hackberry and the like. A drop into the mid to low twenties after repotting and pruning puts these species at risk. I might not move some of the big ones inside, but may opt to leave them under my deck against the house. The buds on some haven't opened yet, which helps a great deal. Some, however, have been pushing leaves for quite some time. This looks to be a near deep freeze coming--possibly below 25 F locally.

We had a very very bad patch of weather in Feb., despite the unnusually warm Dec. and Jan. There was deep, sustained cold for weeks, with lows between 3 and 10 F at night, and highs reaching only into the mid 20s in the day.

Sustained cold after a prolonged warm spell, I think, contributed to alot of die back on collected species, even the stuff I've collected locally. The mulch froze solid through to the ground in my storage areas--which isn't a good thing.

I had complete limb die back on native hornbeam and hackberry, with alot of partial die back of twigs and branches on other species, including Japanese maple and Korean Hornbeam. These were left only with a deep mulch covering over the winter. The trees in a covered cold frame did fine.

After 15 years of overwintering trees, this is the worst year I can remember.