Q.What is causing the black stained leaves on holly bush?
The black stained look is on the glossy side of the leaf. Only a small speck or two show on the back side of the leaf. The leaves are falling off. The berry buds and flowers are plentiful. The weather has been erratic with heat in the 80s this past week. We have not had a deep cold spell for a while. The tree is in the center of our recently replaced deck. I would also like to know how to keep it healthy. Thanks for your help.
Certified GKH Gardening Expert
This sounds like either tar spot or sooty mold. Sooty mold is normally a result of a pest infestation. These articles will help: https://www.gardeningknowhow.com/ornamental/shrubs/holly/holly-problems-holly-leaf-spot-or-holly-tar-spot.htm
Neem oil can be used to treat both. Here is more information: https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm