Q.My Gardenia Bush Is Sick
There is a black fungus on my roof that has washed down on my big beautiful gardenias. Now my gardenias are sick and dying. They look sick and bare. The stems are black, the leaves are almost all black, some are yellow. They just look awful. What do I do? My gardenias always produce big and beautiful blooms that smell the whole place up. I usually give clippings to people and they love it. I bring clippings to work and the aroma fills the office. How can I save my prized flowering bush?

Certified GKH Gardening Expert
This is due to sooty mold. It happens when the plant gets a pest infestation. I would recommend using neem oil, as this will get rid of the sooty mold fungus and kill the pests. Here is some articles that will help you: https://www.gardeningknowhow.com/plant-problems/disease/how-to-get-rid-of-sooty-mold.htm
https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm