stimpson, its hard to tell if they'll come back or not. I'd be inclined to ditch them because even if they do come back they may be stunted. They're easy enough to start from seed or get off a neighbor :') Shastas are very hardy and should have been up and growing strong by now. Even with our cool spring here in zone 1 mine were probably 8-10 inches high by mid-June. Maybe you'll come across some stray seedlings around the plants if they bloomed last year...i'm finding a zillion of them in my flower beds :(