Mine have done the same thing. Lots of new green growth coming up but dead old growth. Today I pruned some of them back. I have some that didn't die back--oak leaf and 2 bush like ones. Can;t remember the names but they have white flowers. All my lace cap and mop head's have suffered die back. Nature's way to have a new start.

My gardenias have been burnt very badly :c(. My tropical lilies still haven't put out any leaves, so they may be toast. Amazingly a few of the lantanas are putting up new growth. All of my perennial salvias are gone. I have been trying to give everything a little extra time in hopes they will send up from their roots but after today's survey I think several things didn't survive the teens weather we had.