It is too early to tell if those plants are really dead or just still dormant from the hard winter. Sometimes you have to wait until June to see signs of new growth. I suggest you be patient and on June 1, if you see signs of new green growth than trim the dead-looking parts of these plants back to new growth. If on June 1 you see no new growth at all than that is your cue to dig in add these plants to your compost pile. The good news is the nurseries should still be stocked with plants in June so you can replace your winter weary specimens with either the same thing or something that is hardier for your area. Maybe Volcano Phlox instead of Cape Fuchsia, crocosmia instead of Hot Lips Salvia and Monkshood instead of Black and Blue Salvia. Keep growing, Marianne Binetti