Here's a video that might help - https://www.youtube.com/watch?v=58iMEgetU_4
I save my potted flowers by bringing them in for the winter and setting them under a big window in our spare bedroom. My Grandma used to save the petals on flowers planted in her flower garden by drying them and putting them in ceramic pots to give the grandkids. My dearest friend dried hers and Mod Podged them on card stock and framed them as gifts for home decor. Our pastor's wife covers her canna lilies with a 5 gallon bucket upside down with insulation around them. My husband gathers the seeds of his marigolds and replants the new seeds each spring for his marigolds again. Lisa, I hope this gives you some ideas.
You can add extra mulch for warmth or cover if they're perennials (or I'll do this with my strawberries that I have potted), but if they're annuals I'd bring the pot inside in your garage or basement and lightly water every so often and keep in a dark and cool place.