Try some annabelle hydrangeas behind the azaleas. Native, tough, and always flower every year. Or oakleaf hydrangea.

I'd try something more uncommon, that ground looks pretty dry for hellebore and hosta, why not try a bevy of different villosa heuchera hybrids? They mix beautifully together with types of native carex and ferns like dixie wood fern and others that can tolerate a bit drier.

What types of azaleas are those?

If this were my driveway, I would not attempt to garden on the verges of it. From what I can make out, you have is a very informal country driveway. The formality of planting along the drive feels misplaced. I would prefer the random drifts of spring bulbs and a few tufts of nearly wild summer annuals just to give it a friendly, but casual feel, then I would concentrate my more serious gardening efforts elsewhere. The car tires will kick up gravel and plenty of dust, and hostas and such probably would not achieve the ideal of your imagination. However, should you eventually choose to pave the drive, that would alter the character of it, and by adding some formal structural bed elements, more lavish plantings might look good out of the way of the swinging car doors and trampling feet that exit the cars.

Just my unschooled observation, but those stacked blocks would feel more permanent if they had some extra-rich soil built up behind them, with your flowering shrubs planted in the nice deep soil. It's like the blocks need to visually perform more of a function than just sitting there giving a visual cue "this is a planter". I'm not expressing that very well, but what can you expect from an amateur?

Thanks oath5 and catkim. Those are Encore Azaleas in the stone beds. Yes, catkim, I do plan on mulching the beds but just haven't gotten around to it yet.

I do like the idea of hydrangeas but wasn't really planning on lining the rest of the drive with azaleas. Would really like something evergreen to go in front or behind the hydrangeas so that area is not completely bare in the winter. Hostas and heuchera will be bare in the winter too. Any other thoughts of an evergreen to complement these plants? As much as I hate to admit it, maybe more azaleas is my answer after all.

I'd suggest you borrow/buy/take out from the library some horticirtural reference books which reference evergreen shrubs/ground covers hardy to your part of the upper south. The Southern Living Plant Encyclopedia which is a sister publication of the west coast Sunset Western Garden Book would be a good source. In my own personal library I've got an old copy of the book by authors Odenwald and Turner, IBSN 0-87511-816-X, titled Southern Plants for Landscape Design which lists quite a few evergreen lower
growing shrubs, ground covers, grasses, rushes and sedges(Carex species), etc which could be used in a zone 7a upper south setting.. I have never gardened or designed a garden in the south, so I can't speak to whether all would do well given your variables of shade and soil moisture. Amongst the lower growing sorts that might serve as effective border plants to the driveway, are the following:
Carex species such as C. morrowi and local native species
Camellia sasanqua cultivars
Luzula spp
Hypericum calycinum
Ilex crenata Halleri
Leucothe axillaris
Liriope muscari
Nandina domestica Harbour Dwarf
Ophiopogon japonicus
Pachysandra terminalis
Phlox divaricata
Sarcocca hookeriana
Saxifraga stolonifeta
Spigelia marilandica
Trachelspermum asiaticum
Vinca minor
Vinca minor Illumination

You might also consider using non-evergreen sorts of things as some of your better adapted local ferns or mass planted lily of the valley or similar thicketing perennials for shade.

You might also browse the list of available shade plants from mail order nurseries such as Plant Delights Nursery in North Carolina.

For better success getting shade plants established with shade and tree root competition, you may need to consider major soil amending with compost and supplemental temporary or permanent irrigation of slower to establish spreading from the roots ground covers such as the Liriopes and Ophiopogons. Especially if your warm season rainfall isn't sufficiently regular to get such plants off to a good start. Looking up recommendations for local north Mississippi native shade plants and grasses could also give you some excellent choices.