Hello all you annual experts!

Generally I don't grow many annuals, I find them too expensive considering they don't come back. Last year I splurged and put some yellow petunias in a large container and liked them a lot. In the fall I put the container in the garage so it wouldn't crack. I looked yesterday and there is a little green here and there on the petunias that were planted in it...mostly near the ends of the plants. Are these plants salvageable as cuttings? Or may it regrow if cut down and watered? Thank you in advance for any assistance you can give.