Yearly hard pruning encourages barberry shrubs to grow into dense, bushy shapes. These shrubs have sharp thorns and colorful foliage, making them both an attractive ornamental in the landscape and an effective visual and physical barrier. Barberries can be grown as part of a foundation planting, shrub borders and mass planting, or as specimen shrubs or hedges. The shrubs can be pruned into neat uniform shapes or formal hedges, or trimmed to follow a natural growth shape.
Japanese barberry is one of the most common barberry shrubs grown in landscape settings. This dense shrub displays bright green foliage in spring. In late summer and fall, the leaves turn orange and red. Japanese bilberry grows 3 to 6 feet (about 90 to 180 cm) tall, with a slightly wider spread. It is a deciduous shrub that loses its leaves in winter. Other common barberry varieties include a broadleaf evergreen called Wintergreen Barberry and the deciduous Mentor Barberry.
Both deciduous and evergreen varieties should be pruned in the summer. Barberry shrubs bloom on woody growth produced in the previous season. It is best to prune as soon as the flowers are done in late summer or early fall. Barberry pruning done in winter while the plant is dormant will result in fewer flowers during the next growing season.
Severe pruning is a method used to prune multi-stem shrubs, including barberry. At least half of the stems are cut down to the ground. When using the severe pruning method for barberry pruning, the oldest stems are cut to encourage new bushy growth. The remaining stems can be pruned back to the desired height and spread.
Perhaps the best tip for barberry pruning is to get an early start right after planting. The first two years are important for shaping a new barberry shrub or hedge. Initial severe pruning also encourages dense bushy growth.
A good tip for barberry pruning when the shrub is old, leggy or overgrown is to use the severe pruning method to cut back the older stems at the ground. Selective pruning can be used to cut the rest of the shrub into the desired shape and size. Sharp pruning shears cut the younger branches effectively, and a pruning saw is well suited for older, thicker branches.
Barberry pruning to remove dead or broken branches can be performed any time of year. Diseased wood should also be removed immediately. The cut should be made in healthy wood about 2 inches (5 cm) or more below the damaged or diseased area. When pruning diseased wood, tools should be cleaned with alcohol or another disinfectant between each cut to prevent the spread of disease.