How Do I Cure a Gray Spindly Fungus Growing on the Bark
How do I get rid of a gray spindly fungus growing on a holly tree?
Certified GKH Gardening Expert
It sounds like you have lichen. It is harmless, but if you want to remove it, this article will help:
If this article doesn't help, take a sample to your local agricultural extension office for identification and suggestions for treatment: https://www.gardeningknowhow.com/ornamental/shrubs/holly/diseases-of-holly-bushes-pests-and-diseases-damaging-holly-bushes.htm