The short answer is very little. I know it is March and everyone is excited to bring out their pruners, but this is one plant to leave alone. Camellias grow very slowly, and they do not need to be pruned into shrubs or kept short. Any dead, rubbing or wild limbs can be pruned but it is not necessary to prune to force flowering. If they have been neglected for years, they may benefit from light pruning to shape and remove unruly limbs.
This photo is a flower of the Camellia japonica. There are three types of camellias easily grown in the Northeast area of Florida: Camellia japonica, C. sasanqua and C. reticulata. C. japonica produces the huge variety of colorful blooms and is the more tree-like form with large, serrated leaves. They start blooming later in the fall and early spring. C. sasanqua is more shrub-like with smaller flowers and leaves. They start blooming in November. C. reticulata, native to China, grows the tallest with a potential of 50 feet. The flowers can be as wide a 12 inches and the leaves are larger than C. japonica. C. reticulata is the most cold-sensitive of the camellias but can live as long as 600 years and it will be difficult to find it at local garden centers or plant nurseries. Camellias are the one plant providing us with beautiful flowers in the cool season.
This camellia is the flower of the Camellia reticulata. All camellias prefer well-drained, acidic soil. Most prefer shade to dappled light, but they will adapt in sun if adequate irrigation is provided. However, it would be better to err on the side of less water than too much. Once established, camellias will adapt to normal rainfall.
Camellias have few pests except aphids, mites or tea scale. When scouting your camellias, look under the lower, older limbs for tea scale and treat with insecticidal soap. Every Southern landscape would benefit from having a camellia in the yard. https://gardeningsolutions.ifas.ufl.edu/plants/ornamentals/camellias.html