Most irregular flower and leaf variegation of camellia is caused by a virus. This is not the same as the more regular pattern of variegation which is genetic in origin (ex. 'Herme' and `Lady Vansittart').
Virus variegation destroys color (in blotches) on either leaves or flowers. Flowers show varying degrees of white, sometimes in beautiful patterns, while leaves show a yellow mottling at random. Often plants that are infected with virus will express variegation on flowers, but not leaves. Camellias with white flowers may be virus infected, but no symptoms will be observed on the flowers. Many camellia growers feel the beauty of the flower is enhanced with the addition of the virus and introduce this to the plant when young.
The virus may be transmitted through cuttings and grafting of non-infected scions onto virus-infected stock. The virus may also be transmitted through natural root grafts. The virus is not transmitted through seed. All seedlings are virus-free.
Once the virus is present in a plant it becomes systemic and may not be removed through ordinary methods. With other types of plants, tissue culture and extreme heat treatments have been used to rid the plant of the virus. These methods are very costly and not practical for the homeowner. There is no chemical control of virus-infected plants. There are several strains of virus present in camellias.
It is believed that the viruses infecting camellia cause little if any damage to the plant. Some reduction in plant growth and hardiness may be observed. The main damage to camellias from virus infection is that they become systemic within the plant and may not be eliminated once infected.
Exclusion must be used to control virus of camellia. For grafting stock use seedlings of sasanqua or oleifera since the virus is not passed from the parent through the seeds. Put all virus-free plants together and virus-infected plants together to prevent root grafts from forming. If virus-free plants are desired, take cuttings or scions from known virus-free plants.