Have several holly hedge groupings. Two sets have some type of disease. One more severe than the other. The one more diseased than the other is in direct sun during afternoon. The other less affected plant is in total shade. Disease initially appears as small brown spots on leaves. Leaves gradually shrivel and fall off. Plant attempts to regenerate itself but is losing battle and foliage becoming very sparse. Help! From northern state and have no experience in this type of bush.
Disease in Holly Bushes
Certified GKH Gardening Expert
The sounds very much like Holly Leaf spot.
There are several fungi that cause this issue.
It's important to remove and discard of the diseased material.
Here are some links with more information and how to treat the plants.