Most dianthus are herbaceous, evergreen perennials. Some species can be very short-lived. There are some that are biennials, like some of the Sweet William varieties. Some people use dianthus AS annuals, and there is nothing wrong with that, but they don't belong in that category.

I live in a zone 7a/b, too. We have some dianthus cultivars that have been in the ground for about 7 years, since we moved here. They need to be divided every couple of years or they make a solid mat of icy blue foliage, but have not disappointed us with their blooming.

If yours aren't looking so great, perhaps you might consider soil or weather conditions. It's been a very unusual winter for many people, and some have had lots of rain and then more rain. Dianthus is pretty darned tough, but it does not like saturated soil. They are also not without their pest and disease issues.

We have very heavy clay soil here, and though the dianthus has flourished up to now, I'm sure keeping an eye on them during this warm, rainy winter we've had.

Thanks for the info. I've heard varying things on whether they are perennials, biennials etc. I'm not sure what kind I have in there. The soil conditions have definitely been wet....the bed that they are in gets all the rain off of the roof as well, so I'm sure you can imagine....

I'll leave them as is and see how they do once we dry out a bit. Eventually I'd love to put gutters on the front of the house so that bed doesn't drown!

Thanks!

Nearly all dianthus are perennials. I suspect that the problem with yours is due to the saturated soil. There are many plants that will suffer under those kinds of conditions.