Definitely hot summer can be brutal on plants. You might want to check what variety you planted whether you planted, Japonicas can take better the sun and Sasanquas do better in the shade/part sun. Wish you the best for your new Camellias.
You can search the USDA zone and see what zone you live in and see what variety of camellias could grow well in your zone. Many new camellias varieties can grow successful in temperatures as low as -10°F/-23°C like Camellia "Polar Ice", "Snow Flurry", "Winter's Charm", etc.
@@user-sanazeki oh, I think I got it now! This is in the east coast of USA, with temperatures in winter as low as 20-30°F and summers as high as 90-100°F
It depends on the location, too much sun, will burn, too little they will grow leggi, it also depends on the variety, Japonica do better on the sun, Sasanquas do better in the shade, although they need some sun, part shade/part sun.