Viburnum shrubs include deciduous and evergreen varieties, most of which produce creamy white flowers in spring or summer and bright red or yellow berries in the fall. Most landscape types reach 2 to 5 feet in height, but some viburnums are more like small trees and can reach up to 30 feet tall. Proper pruning helps control the height of the shrub while also keeping it well-shaped and healthy. Prune viburnums in early spring before new growth begins.
Inspect the shrub for dead or winter-damaged branches. Cut these out with clean shears, making the cut flush with the main branch or trunk to which the damaged branch is attached.
Locate any crossed or rubbing branches in the interior of the plant. Rubbing damages the branches and eventually creates an entrance for insect or disease. Trim back the crossed branches to their base.
Cut back any overgrown branches around the sides. Cut these back to within ¼ inch of a leaf bud nearest the desired length of the branch.
Trim down the top of the viburnum hedge to the desired height, making each cut within ¼ inch of a leaf bud. Remove no more than one-third the height of the viburnum each season.
Evergreen viburnums tolerate severe pruning and shearing, but may not flower the first year after such a pruning. Yearly maintenance pruning is preferable to severe trims every few years.
Do not prune in summer. Summer pruning causes the viburnum to produce excessive sap and the plant is also more susceptible to disease through the cut surfaces.