Well, your location is way out of my area of expertise but what about milkweed or hibiscus or cardinal flower(all hummingbird or butterfly plants). I am in a very dry area, so hopefully someone nearby will chime in. Do you have a County Extension Office you could contact - they are a wealth of information on local/native plants. Good luck to you and happy gardening!

Angie, here's a link to UGA's Native Plants for Georgia. Just skimming through the shrub section, I saw several that matched your size requirements. You may be able to find some that will suit your site. A rabbiteye blueberry might be nice.
Kat

Here is a link that might be useful: Native Plants for Georgia, part I

Here, I'd say bee balm (hummingbirds love the red ones) as do the bees. I just don't know if they would mildew in your area.

They don't mind moist soil (we have clay) but we also have a dry climate during the day...with humidity at night, from the creek. Up to 80% and the bee balm do great :)

Here's a picture...the bee balm is on the lower left, with the red flowers. It normally grows about 3-4 feet tall. {{gwi:51649}}From Lavender's Garden

This post was edited by lavender_lass on Sun, Apr 6, 14 at 16:27

How about an ornamental grass? Amazon Mist is really pretty and likes a moist environment and partial shade, so should grow well there. You could plant more than 1 to get the width you'd like to have. Birds love to nest and hide in the foliage and it is interesting all year round, providing wildlife habitat for every season. Other options: Red Rooster Carex, Alternifolius Cyperus, Isocladus Cyperus, All Gold Hakonechloa macra, Aureola Hakonechloa, Live Wire Isolepis, Strawberries and Cream Phalaris, & Pony Tails Stipo. They are all hardy in your area and are perennials as well. Hope you find something you like!

Here is a link that might be useful: Ornamental Grasses

Thanks guys for the suggestions! I really do appreciate them. The space is still empty, and I am still undecided. I considered Black Chokeberry, but a friend said it will hedge up and isn't all that interesting. I already have host plantings for most of the butterfly species that visit my yard, and I think I am up to 13 Butterfly bushes now. In addition to that, I plant plenty of Zinnia and buy Lantana each summer. So, the butterflies are fairly well covered in my yard. I have Pyracanthas, Cotoneaster, and Crabapple for fruits and berries. I really do want something which blooms for that space, so that it will be really useful to the bees. A Blueberry would be great, but I don't think there is enough sun there for it. I know that it will finally come to me!

As mentioned by lavenderlass, beebalm is great for hummingbirds and bees - the variety Jacob Cline is supposed to be fairly mildew resistant and Raspberry Wine can take a little drier conditions. It blooms most of the summer for me in partial sun conditions.

Thank shillanorth. I do love Bee Balm, but I have TONS of it already in the yard. It proliferates like crazy here in my yard. I finally made the decision for the empty spot, and it has been planted now. I chose Mayberry. (Vaccinium elliottii) I am very excited to see how it does there. Thanks for all of the suggestions. :)

Ah, decisions, decisions!!! I am not familiar with this shrub but it sounds like something in the blueberry family - post us a picture so we can see!

bandjzmom, do you mind sharing the source for your Vaccinium elliotti? Did you buy it commercially?
Thanks.

Kate, I bought it from Ron Rottman on eBay dogwood@eritter.net. I realized that there may be some discrepancy regarding specific species after I had ordered. I do know that I got "a" Highbush Blueberry anyway. :) Are you affiliated with Growing Wild?~~Angie

Angie, thanks for the info. No, I'm not affiliated with a nursery. I just wondered because the link I posted above said V. ellioti wasn't available commercially. I'm always interested in finding where I can buy natives.

Well, if you Google Vaccinium elliotii, you will see that Growing Wild Nursery out of North Carolina lists it for sale for $14. They mention in comments "this plant is sometimes listed as Vaccinium corymbosum; Vaccinium elliottii is very distinct, having much narrower leaves." The one that Ron has is listed as " Vaccinium elliot."
I was really looking to get the Mayberry which is also a butterfly/moth larval host plant, but I think that what I got was not exactly what I was thinking. Still, it's a native Blueberry and will satisfy a lot of what I was hoping for, so I am good. It's all a bit confusing. :)

It only just occurred to me, and I should have mentioned it before, but blueberries are more productive if you have two different varieties that bloom at the same time to cross pollinate. However, they will still bear fruit with one, just not as much.

Thanks Kate. I had learned about that in my readings, and I do think that I will see about finding another spot in the yard somewhere to add another Blueberry bush. I can't wait to see which birds partake of the bounty. :)

Purple salvia is a perennial in zone 8 and it is very popular with hummers, bees and butterflies, you can cluster some and next spring they should be back bigger. They have nice color and will bloom for months if you cut off the spent blossoms.

no one mentioned coral honeysuckle.

Hope you have lots of birds and butterfly's.