Buzylady, I've found with my Mums they will always come back for me,
unless something killed them.
I leave mine in the ground all winter and they really look dead in the early spring
and last year's top growth is dead, but they always bounce back for me when it starts to warm up.
You will start to see the new green starts coming up at the base of the plant
and that's when I cut the old growth off.
Don't lose hope yet, and save some seeds for me when it comes back.