That looks like the standard variety of "annual" Dianthus, Cinder. They're usually sold in 4 or 6 packs in the spring along with the other annuals, but they almost always come back year after year--at least for a few years. I have some that are at least 4 or 5 years old. They tend to bloom for a pretty long time, and if you take the time to deadhead individual flowers--a time consuming project--they'll bloom even longer. Or you can wait till they're mostly to the end of their main bloom and cut them down most of the way, and they often come back and bloom a second time. If you don't cut them down at all over summer, be sure to cut them down most of the way going into winter--they'll start blooming pretty early in spring, and it's harder to cut out the ugly dead stems after they start getting new growth. If you like it/them, watch for them next spring in the big box stores and pick the colors you like the best!

Skybird