Clematis are notoriously mislabeled. Not only have I gotten mislabeled clematis from the big box stores, I've gotten mislabeled clems from reputable nurseries and mail-order sources as well.

ALL plants at Home Depot, Lowe's, Wal*Mart etc. are commonly mislabeled!

Not just Clematis. I see mislabeled plants and plants that won't grow in my zone pretty much every trip. I still go and look for bargains but I don't buy blooming plants unless they are blooming if I want to be sure of "who" they really are.

I have also had problems with packaged bulbs and seeds at big box stores.