I have two in pots waiting to be planted but I am in Zone 7b/8a, very different from yours. I can plant a camellia in the middle of winter as long as I water it when winter is dry and as long as I mulch it well. I have also waited until Spring too. That one was bought when temps were much colder and I just could not find a weekend with temps comfortable for digging so I gave up and kept it in the garage until late March.

The danger from the frosts that you mention may affect the flower buds and some tender new growth but I doubt it would kill the plant. They are pretty hardy and normally can be planted any time. The only one I have planted in the summer "is not with me anymore" but its demise was due to the dogs chasing a squirrel and breaking the main trunks to $$hred$$.

Here is a link that might be useful: Planting Camellias by the American Camellia Society

Thanks for the advice and link - I'd already been scouting around their site for hints. If I was able to plant it in the ground I wouldn't have been as concerned. I'll see how she does. Thanks!