Q: I need some assistance with how to care for leatherleaf mahonia plants. I have some very large samples in my yard.

I recently purchased this home and I do not have any experience with them. Should I trim them? If so, when and how much?

A: Mahonia is pruned like nandina – by cutting the stems at different heights so there are leaves near the ground as well as higher up, giving a rounded, shrub-like appearance.

Count the several stems I see emerging from the base of the shrub and divide by 4. Not that some stems are deeply furrowed; these are the oldest stems. Cut the tallest and oldest fourth of the stems at 12 inches, cut the next group at 18 inches and the third group at 24 inches.

The shortest and youngest stems are left unpruned. Their foliage is what will power the recovery and fresh foliage you’ll see in summer.

mahonia bush