I have one holly berry (China girl, my sister calls it) and many non-berry bearing (China boy?) bushes around my acre yard. I think I've figured out how to get the China girl to bloom almost every year, but the China boys are so gangly and unattractive. When should I trim them and to what degree?
Holly Berry Bush
Certified GKH Gardening Expert
You should not cut away more than 1/3 in any one year. Also, any pruning should be done in winter, though doing so now is ok. This article will help: https://www.gardeningknowhow.com/ornamental/shrubs/holly/trimming-holly-bushes-how-to-prune-holly-bushes.htm