Viability of butterfly bush
I have a butterfly bush that was planted last year. At this date, May 2nd, the bush has not started to show any green. When I take a limb between my fingers it is not brittle, rather bends easily. I live in Zone 6 and most everything else is showing signs of life.
I would give the plant more time; especially since the branches sound alive and viable. You may watch at the base of the perennial. Often time it will grow from the root, not the remaining spent branches.