Yes, I would say that that they are getting sun bleached. Here in Texas, I selected planting locations where the canopy of Crape Myrtles provides shade by 10-11am due to the intensity of the summer sun. A good way to diagnose this is by observing the leaves veins and by comparing the leaves that the sun hits against the leaves further inside the bush. The leaf veins in your photos are yellowing out. And the leaves further inside the bush look deep green while the ones who bear the brunt of sunlight look completely yellowed out (including the veins' area). This problem can be normal for some folks during winter because the canopy of deciduous trees may not be there to provide shade. It is also normal on newly planted camellias. In both of those two cases, it will pass. However, you do not want this condition to go on for a long time as some leaf-spotting fungi can infect the sun-bleached leaves. Lack of iron is a very common problem but definitely not what you have. Observe the leaves in your photos again. If you had iron chlorosis, the veins in the leaves would be a deep dark green while the rest of the leaf would be yellowed out. While you are at it, check the soil with a soil test. These should be done about every few (2-3) years but I personally do them about every 3-5 years. This would be a way to double check that there is no lack of certain minerals in your soil. Sort of a safety check. Your state's Agriculture Extension Office and local nurseries can assist with this. Luis

We would be better to read many articles about the research on this subject by Dr. Parks or Dr Ackerman. I do not know much about camellia genetics because I background is a combination of Dairy science and Vet. M Science. I did carry out a large portion of cross pollination for many years between two camellia species and have produced many interesting seedlings. I am not intend to confirm the seedlings in what kind of genetical make-up. If the seedling carries a desired trait or appearance, that is good enough for me. Camellia breeding has been a consuming task. But I found some principles and shortcut to make the job easier. It becomes my fun hobby without too much of labor and mind twisting. Reading and understanding are very important. Without actual doing, we would be unable to gain our own first-hand experience and personal thinking.

You can see the Optional Link URL. They are really yellow. You can see the article of yellow camellias in the magazine ICJ of 1997. Also the article about the camellias of the park TAM Dao of Vietnam in the Nº19 of the magazine Camellia of the SEC. Regards. Here is a link that might be useful: Yellow Camellias in Rural Palaces

If you can provide a micro-climate where it can flourish, that would be great! ;o)) I will be glad to send you some of the heat that we currently have if you think it will help raise your zone from 8a to 8b. Hee hee hee! PS - cut off some of the weeds so they do not compete with the camellia.