Pruning patio standard holly tree

Question

I have two patio standard holly trees. One is ordinary holly the other variegated. How and when do I prune them to maintain their shape? I am aiming for a round shape.

Answer 1

This article will help you with the basics:
https://www.gardeningknowhow.com/ornamental/shrubs/holly/trimming-holly-bushes-how-to-prune-holly-bushes.htm

Pruning is basically sculpting the plant. If you are aiming for a round shape, then start shaping them that way. If you need to remove more than a few inches to do this, you may want to take a little off this year and then do more next year, shaping the plants gradually.