We have a well established holly bush that has been doing good since we moved in three summers ago. This year, however, the leaves are turning almost black and are falling off. This is on the entire bush, not just spots here or there. It almost looks like the leaves have been burnt by the sun. We have had a lot more rain this summer than usual, but temperatures and sun exposure have remained the same from previous summers. I can't figure this out. I would hate to lose this bush. It normally does so well. Please help.
Holly Bush Looks Like It’s Dying
Certified GKH Gardening Expert
As for the black leaves, this sounds like either tar spot or sooty mold. Sooty mold is normally a result of a pest infestation, and the most likely in your case. Neem oil can be used to treat both the pests as well as the fungus. These articles will help: https://www.gardeningknowhow.com/ornamental/shrubs/holly/holly-problems-holly-leaf-spot-or-holly-tar-spot.htm