Guess that's where the term "ditch lilies" came from. The common orange daylilies..you see them everywhere. I'm sure other posters can come up with a nice list of ever-blooming mixture of plants for you.

What i grow in my steep, deep unmowable ditch is lysamchia nummalaria aka creeping jenny. Stays flat, spreads nicely, but is easy to pull if it gets out of bounds. Little yellow flowers. Can handle full sun, and periodic flooding. It will look rough during a drought, but should bounce back. Comes in plain green or hot chartreuse. It stay flush with the ground- so now mowing, trimming or other maintenance.

If you have a barrier of some sort, you could consider mint, but be aware it's very invasive if there isn't a driveway or something solid like that to stop its spread. There's also a fairly pretty creeping charlie that is variegated that works well. It also can stand flooding. I also encourage wild violets in my ditch. Anything that's green, stays low and doesn't need trimmed or mowed is welcome. Grass is not.

Welcome, fellow Yankee! You're going to love the Carolinas!
I absolutely agree with Tam, Lysimachia will be a very good choice. If you want to save money, pay for the largest pot of this plant you can find and then divide it into small pieces. It roots and spreads very quickly. Pop a few bulbs of Leucojum in with them for added, early Spring interest - they tolerate being wet for 24 hours.

Here is a link that might be useful: Leucojum images

I have to say the best thing may be to plant a "Rain Garden" in this area. Check this link below to see if this will help.
http://www.bae.ncsu.edu/topic/raingarden/

Here is a link that might be useful: ncsu rain gardens