Never lived in Georgia, but based on what I know about hydrangeas and Georgia's sun, I think your oakleaf in said location will be in a constant state of suffering from the heat/sun/drought and you'll not be pleased with it.
Sorry.
Re: drainage.
Mix in a soil sharp builder's sand and plant high.

Yes, I think it will be an issue of leaf scorch and a constant need to put water on it.

Have you considered a Red buckeye for that location? The foliage doesn't last as long in the fall (not very long at all actually).

Don't laugh, but a native shrub for good fall color is Blueberry. Mine turned bright red last year. Three gallon blueberries are arriving in stores this month ... be sure to get the V. ashei (rabbiteye) ones if you're interested. There's a post about it on the Georgia forum.

Thanks for the advice ego45 and esh_ga! I think I will end up planting an oakleaf, but in a different spot (dappled shade in the afternoon) where it will have a decent chance of thriving. I think the full afternoon sun would be too harsh.

Esh, I looked up the blueberry and the red buckeye, but I am really wanting to get 3 or 4 season interest, so I think I am going to go with the evergreen you suggested to me in the shrubs forum (the Lyonia)! Thanks again so much.

I have a Snowflake planted on the east end of the garden. It gets morning shade from a large willow oak across the road. The rest of the day it is in full sun. It is the fullest and largest of my 10 oakleafs. It has withstood the last two Alabama summers of hard drought. It always blooms like gangbusters.

I agree with tsmith, as to amount of direct sunlight an Oakleaf Hydrangea can tolerate. The best blooming / growing cultivars in my garden and throughout the neighborhood, receive full afternoon or all-day sun exposure. Haven't experienced or observed any leaf scorch at all throughout the many years they have been growing.
Be sure they receive good drainage, as they absolutely will not tolerate wet feet!
Mulch and keep watered for the first couple of years, after the roots become established, you can pretty much ignore them.

I just love any paniculata hydrangea....I have two
Oakleafs planted in full sun also. I'm surprised at how
well they are doing. I do keep a watch on them, however,
no problem yet. Hopefully, I can get something planted
to shade them a bit this spring. Thinking about the red
buckeye that I recently got thru a trade.

Margaret

Thanks for all your advice! I bought my plants last week and I will be putting in a 'Pee Wee' in a place that gets full morning sun and is in a little shade in the afternoon. I am so loooking forward to this beautiful shrub.

I will plant it high and use plenty of pine needle mulch!

I've had oakleafs in full sun and in part shade and I would say they perform better in full sun (provided they get watered the first couple years. You'll get better fall color, more blooms, and a fuller shrub in full sun. In shade they tend to be leggy and have fewer blooms. One benefit to shade is that the blooms stay white longer.

One advantage of living in the southeastern US red-clay belt is that the soil is very moisture-retentive. I have Snow Queen in full afternoon sun here in Virginia, and it does very well. Beautiful plant with lots of blooms. I don't think it would do well in 5 hours of hot sun if the soil didn't hold its moisture.