I believe this is an aster. Not really thrilled with its performance, but I'll wait to see next year. My question is how can a plant have 2 completely different leaves?

I bought 5 dianthus plants at a box store. They were $1 each on the sale rack. Is there any saving these? Should I whack them back to about 2-3 inches and plant out of the way, maybe a little shade since they're not in the best of health? What to do and where to plant. Those are the questions!