Q.How to treat camellia disease
My camellia is ten yrs. old and has never bloomed. Now it is covered in black mold. Today I washed it with dish soap and water, then sprayed it with a lime sulphur spray. Is this ok or is the lime not good for it?

Certified GKH Gardening Expert
The lime is probably not too good for the plant, but I can say that your camellia sounds like it's suffering from sooty mold, which more often than not is brought about by some type of pest, like aphid or mealy bug. I would recommend washing the plant down with water to remove any excess lime or soap from the plant and then treat it with neem oil. We have found it to be very effective against these kinds of pests and it will also help treat the sooty mold fungus. These articles will explain more:
https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm
https://www.gardeningknowhow.com/plant-problems/disease/how-to-get-rid-of-sooty-mold.htm
https://www.gardeningknowhow.com/ornamental/flowers/camellia/sooty-mold-on-camellia.htm
Once the plant has returned to health, adding some phosphorus-rich fertilizer or bone meal to the soil should help encourage the blooms.