One of the joys of being in the south is the longer growing season. This is enhanced by newer varieties of some spring shrubs that continue to bloom over the summer and into fall, or rebloom in late summer and fall. Two are notable for southern gardens - Endless Summer hydrangeas and Encore azaleas. These terrific shrubs are hardy well to the north, but are unlikley to bloom as late as in the south. They both flower on new wood and so will continue to produce sporadic blooms throughout the summer after the first flush of color in the spring, and culminate with quite a good show of color when the cooler fall weather arrives. This is perfect timing for the south, as the summer is generally too hot to sit and admire things in the garden!
If you haven't yet tried these varieties Google the name and you will be taken to the sites that give information and retail information.