With its holly-like leaf and fragrant yellow blooms, leatherleaf mahonia (Mahonia bealei) adds year-round interest to shaded gardens where few other shrubs will grow. They prosper within U.S. Department of Agriculture plant hardiness zones 6 to 9, where they reach a mature height of 4 to 6 ft with an open, spreading growth habit. Leatherleaf mahonia shrubs grow gradually and require very little pruning to control their dimensions. However, heavy pruning in late winter and occasional pruning during the summer months will improve their look by creating a fuller shape with denser, more attractive foliage cover.
Water leatherleaf mahonia shrubs deeply the morning prior to pruning them so the stems and foliage are well hydrated. Trickle a garden hose at the base until the soil feels saturated from the top 5 inches.
Clean and sanitize a set of bypass shears before using them on the leatherleaf mahonia. Soak the blades for five minutes at a bucket of cleaning solution made up of 1 part chlorine bleach and 3 parts water. Rinse the bypass shears and allow them to dry prior to use.
Put on heavy leather gloves and a thick long-sleeved shirt before pruning leatherleaf mahonias because their leaves are extremely spiny and sharp. Wear goggles to shield your eyes in case the plant is quite big and overgrown.
Prune leatherleaf mahonias severely in late winter to promote fresh, new growth. Cut back the entire shrub to within 12 inches of the ground using your newly washed jump shears. Leave a few of the tall divisions to keep the shrubs’ height, if needed.
Prune off any dead or damaged branches as they appear throughout the summer months. Snip off the undesirable branches where they emerge in the nearest lead division. Make the pruning cut almost flush against the lead division.
Selectively remove growth in the center of this leatherleaf mahonia to accentuate its receptive, tiered growth habit. Snip off any small side shoots that have appeared along the lead branches between the key tiers.
Prune back all but the largest, most robust stem to create an erect, single-stemmed tree. Cut the encompassing stems to ground level to force the shrubs’ energy into the central stem. Keep to cut back the unwanted branches year-round to keep its physical appearance.