UC Cooperative Extension Ventura County
669 County Square Drive Suite 100
Ventura CA 93003
Monday - Thursday: 8 am to 5 pm
Friday: 8 am to noon or by appointment
Fungi on Camellias
There are several fungi that can produce a flower rot in camellias. The Botrytis gray mold fungus and a Sclerotinia white mold fungus are the most likely causal agents. Many treatments have been tried to manage and control camellia flower blight. To date none have been completely successful. The spores of the above fungi are airborne and can travel a mile or more on the wind. Moist spring rains and our ever-present foggy conditions and mild temperatures provide an ideal environment for these pathogens to infect and damage flowers. So, even if you are very careful to keep diseased flowers picked up and keep your plant sprayed with fungicides, the chances of continued occurrences of flower blight are still high.
At one time I recommended control practices, but have stopped doing so because I have found it is a futile effort. One recommendation I can make, which may be of some help in reducing disease incidence. There are some 3000 cultivars of camellia. Single flower structure camellias tend to be less susceptible to disease than the semi-doubles, peony forms and formal doubles. You may want to take this information into consideration when planning your camellia garden.