How to Prune and Trim Bushes and Shrubs

Damaged, dead or diseased stems can be a nuisance to shrubs and plants, as they attract insects. You should remove these stems when you see them.

Common upright hedges include privet, hawthorn, buxus and escallonia hedges. Trim these upright hedges twice a year, typically in the spring and early fall. If you have a flowering hedge, hold off on trimming it until its blooming is complete. You can also prune these plants once or twice annually to remove any dead branches.

Deciduous hedges and shrubs include hydrangeas, butterfly bushes, lilac bushes, beech hedges, forsythia hedges and many others. Generally, deciduous hedge and shrub pruning consists of thinning out the existing growth, which can promote additional growth of the remaining branches. This technique involves using hedge clippers or shears to cut off a branch at its point of origin. For deciduous hedges, focus on trimming to your desired shape and removing any diseased or damaged stems when you see them.

Hydrangeas

If you’re wondering when to prune a hydrangea, it depends on the type. Some, such as bigleaf hydrangeas, bloom on old wood. The best time to prune this type of hydrangea is after the plant has finished blooming for the season, typically in early fall. Conversely, prune hydrangeas that bloom on new wood, such as smooth hydrangeas, in early spring.

Prune bigleaf hydrangeas by removing some of the dead wood, but make sure some remains for new blooms. You can prune and remove up to a third of the plant if you want to reduce the size. If you’re pruning a smooth hydrangea, shape it with light pruning if you want it to produce many small blooms. If you cut the plant back further, to about a foot or so above the ground, you’ll get larger flowers, but they’ll be fewer in number.

Butterfly Bushes

When new growth appears in the spring, it’s time to trim your butterfly bush. While some people prune their butterfly bushes in the early fall, we don’t advise this in colder climates, as it can make the bush susceptible to damage over the winter.

Lilac Bushes

Lilac bushes can have an irregular, rounded shape. Trim your lilac bush right after it’s finished blooming in the spring. We don’t recommend pruning a lilac bush in the early fall.

Beech Hedges

Trim beech hedges in early June to keep the bush fuller. Then, trim again in early August to promote new leaf growth. Taper more narrowly at the top to allow sunlight to reach the entire hedge.

Forsythia Hedges

Light trimming can help forsythia hedges keep their rounded shape. To maximize full flowers, prune forsythia hedges after they’ve stopped flowering. Be sure to prune before mid-July to allow time for the plant to develop new buds.

When pruning and trimming evergreen hedges, focus on maintaining their natural shape. Consider trimming the hedges to remove individual branches rather than shearing away multiple branches at once. Trimming creates a more natural look that’s easier to maintain. Evergreens with narrow leaves, such as pines or junipers, don’t require extensive pruning. Cut the tips of these plants annually. Young pines may require cutting the top branch back to a dormant bud to allow for more-even growth. Evergreens with broad leaves, such as azaleas and pyracantha, are also low-maintenance plants. Focus your annual maintenance on removing old or weak stems and shaping the plant to your desired look.