You may have the Camellia sasanqua variety, which blooms in autumn and early winter. The blooms are small and delicate. The camellia you may be more familiar with is the Camellia japonica, which is very popular in the Sacramento area. Depending on the type, blooming may take place from fall through early spring. My plum tree is oozing sap on the trunk and the limbs.
Gummosis can result from a number of causes.
Plums tend to ooze sap more than some other species. If the bark looks healthy, there is nothing to be concerned about. If, however, the tree has been injured or is suffering from environmental damage or insect attacks, it needs help. Be sure the tree has proper drainage and is not exposed to mechanical injury from weed eaters or mowers. Use appropriate pruning techniques.