Every year, my Camellia sasanquas get leaf gall.
This disease is caused by a fungus, Exobasidium camelliae. Infected leaves become fleshy, thick, and discolored.
While disgusting to look at, the misshapen leaves don’t do any serious harm. The disease may be controlled by removing the infected pieces and disposing of them in the trash (not the compost). It’s best to do this as soon as you spot them, before the galls have a chance to fully develop and release their spores.
Moist and humid weather produces favorable conditions for camellia leaf gall to develop. We have certainly met those criteria this spring. I have never seen the disease on my japonicas (the spring bloomers); only on the sasanquas (fall bloomers). Take a look at your camellias and if you spot the problem, don’t reach for a spray. Just nip off the swollen leaves, clean up any that have dropped, and your plants will be happy again.