Camellia – Oedema (Edema)
Q: My camellias were planted in June and get afternoon sun for 2-3 hours. I have watered them on a regular basis during the summer as with the other plants that were planted. I’ve not fertilized them. What is going on with the leaves?
A: The corky blisters on the back of the leaves pretty well confirm that you have leaf oedema, a swelling of leaf cells in response to too much water. You might have overwatered the site, fearing that hot weather would harm the shrubs.
In any case, I think they will come through just fine. Stop watering and give the plants more sun by limbing up the tree. The symptoms should gradually disappear as the plant grows larger.