How did you store them, and what kind of condition are they in now?
I store mine in damp peat, and by spring they are starting to sprout. If
yours sprouted, but never got in the ground, they may have exhausted
themselves or rotted. On the other hand, if you stored them dry, they may
have dried out too much.
If by some lucky chance when you examine them they seem firm but not
withered, you could try potting up a few and growing them indoors if you
have a very sunny spot for them. Then, come spring, you could divide the
potted ones and replenish your stock. Even if they are in good condition
now, I doubt they would last another winter, so potting up may be your best
This is all just surmise on my part; perhaps someone else has experience
with this situation. At any rate, good luck, and if they don't make it,
it's just a good reason to buy some cool new varieties next year. Horn
Canna farms has a good selection at reasonable prices:
Zone 6, Southcentral PA
Click to see the full signature.