Don't give up yet. I planted one in a pot last year and it took a long time to poke through. That's why this year I bought some already started ones at a local nursery.

As gigisgarden said, they take a long time to get going. One thing you might want to do in the fall is to dig them out, pot in black plastic pots (or whatever you have) and bring them indoors before frost. If you have a place to keep them going (not necessary thriving, but not dormant), they won't take as long next year to put out leaves.