I have had a fall blooming camellia for 8 years but it has only bloomed once or twice in all those years. I planted two but the other one died after only a couple years. I do know there are species that are said to be hardy to zone 6 but don't remember more than that. After a trip to Georgia I decided I wanted camellias and did a lot of research and ordered these two from a Georgia firm specializing in camellias, but lost interest when they didn't bloom. I am in z 6b.

I have not grown them in the ground, but we care for them at the nursery. The varieties that are hardy here (to my knowledge) are Korean Fire and April Remembered....I do know it takes a lot of soil amendments to keep them happy if you have red clay! Good luck and post pictures if you decide to plant!

My daughter had one when she lived in Baltimore MD. It was with the house they bought, and it was pretty good sized. They did not cover it during the winter and they had some harsh winter. Unsure what the little lady who had it before did.
mo

Camellias want rich acidic soil. Our soil in VA is acidic but I still add lots of peat when planting camellias. Baltimore has similar growing conditions.

The biggest problem for me, and perhaps for folks in Oklahoma, is wind. If I can protect camellias from the wind, they grow fast and are drop-dead gorgeous. Sad to say, I've lost more than I want to count after fairly short periods of cold winter wind. Might have better luck if you wrap them in burlap, and stuff straw between the tree and burlap.