Q.Why Is One Of My Japanese Holly Shrubs Suddenly Dying?
I’ve had four Japanese Holly Shrubs for six years and three of them suddenly had major growth spurts, while one mostly stopped growing and has dropped its leave on one half of the plant. That side it looking very woody and the plant is significantly smaller than the rest. What could be the problem and is it amendable?

Certified GKH Gardening Expert
It likely has something to do with being in that corner. The shrub may not get as much airflow, sun water, or some other factor, as the other shrubs next to it.
There may not be a good way to fix the problem, but keeping any dead material trimmed can help, some.
Here is an article that will help you with the care of the shrub:
https://www.gardeningknowhow.com/ornamental/shrubs/holly/japanese-holly-care.htm