Can I trim the bowling ball bush by half its size?

Question

They have grown larger than 3’x 3′ and I need to either trim them back a lot or remove them completely.

Answer 1

Here's a link about caring for your shrub.
https://www.gardeningknowhow.com/ornamental/trees/arborvitae/mr-bowling-ball-arborvitae.htm

You may be better off moving this shrub than pruning it down, especially that severely. These plants don't necessarily recover from pruning, and you may end up with permanent bald spots on your shrub where the greenery can't grow back. Plus, you should never remove more than 1/3 of a shrub at any time.

If you do decide to transplant the shrub, you might want to consider pruning its roots to keep it from growing larger. I'm including an article about how to do that.
https://www.gardeningknowhow.com/ornamental/trees/tgen/root-pruning-trees-shrubs.htm