We got about 20 below F for less than a week here this winter. For
this area not really all that cold but I had die back on very specific
plants. Everyone of my 3 year old St Croix grapes (but no other
varieties), all of my Korean bush cherries (but none of the Nanking),
& a running 4 ft high bamboo (phyllostachys aureosulcata?) which was
starting to get invasive. As for strange bloom times, I have a persian
lilac flowering for the first time, just now starting to form flowers &
looks like it'll flower in about a month or so, all of the other lilacs
here finished flowering a couple weeks ago.