Those don't look like dianthus. Dianthus are in the carnation family and have flowers smaller and similar to them. Not sure what this is though. It has a yellow center like a daisy mum or aster. When does it bloom?
I am so sorry, the color is pretty accurate, but uploaded the wrong picture. Added the pick from the original plant, blooms from spring until frost if I keep it trimmed. I apologize for the mistake. I don't want to steer anyone wrong. Come spring I will post the Mums as live plants.