I have 5 year old bearberry that is suddenly turning black. Our last summer was the hottest, driest in history if that’s relevant. Do I have a problem?
First (before I forget) zone refers to your USDA plant hardiness zone, which according to the information is 9a. https://www.gardeningknowhow.com/planting-zones/usda-planting-zone-map.htm
On the subject of bearberry, climate extremes could definitely cause such symptoms as blackening of the leaves. The heat and dryness could easily have stressed the roots, then the shorter days and cooler temps of winter might have allowed a fungus to start. You might start some cuttings in pots, to use as replacement plants in the spring. Otherwise, basically hang in till the days grow longer, cut out the blackened parts, and you should see regrowth. This article has some tips on bearberry: https://www.gardeningknowhow.com/ornamental/groundcover/bearberry/growing-bearberry-plants.htm