Neal, They are all the cold hardy
Ackerman Hybrids. I have purchased them mostly from
Greer Gardens. GG has a good selection and offers a replacement policy for failed plants. It's not cheap for me to have them shipped all the way across the country, but I really love them.
Camellias come in two types, the fall/winter bloomers and the spring bloomers. Most of mine are the spring bloomers, mostly because I like red blooming Camellias and there don't seem to be any reds among the fall bloomers. Last year, I did find a neat new one at a local Nursery, but I've been having to treat that one constantly for a spotted fungus.