Deciduous shrubs that are overgrown or damaged by animals can be a real eye sore in a landscape planting. With proper pruning these shrubs can usually be brought back to a more pleasing form.
The general rule for pruning deciduous shrubs is to prune those that flower in spring right after flowering. Examples of shrubs that bloom in the spring include common lilac, forsythia, and double flowering plum. Deciduous shrubs that bloom on new growth or are grown primarily for foliage should be pruned before they leaf out in the spring. Examples include dogwood, barberry, and smooth leaf hydrangea. The general rule for pruning changes when it comes to overgrown shrubs or those damaged by animals. These shrubs should be pruned in the spring prior to new growth regardless of when they flower.
Shrubs that are overgrown can be brought under control by renewal or rejuvenation pruning. Renewal pruning is done by removing up to one-third of the oldest stems or trunks by cutting them off near the base of the plant. The process is repeated yearly until all the old stems or trunks have been removed. New stems will emerge from the base of the shrub. New stems are brighter in color, especially for dogwood, and will eventually produce more and better flowers.
Rejuvenation pruning is the removal of all stems or trunks by cutting them off near the base of the plant. This pruning is more aggressive than renewal pruning but it accomplishes the same goal in a shorter amount of time. This is perfect for hopelessly overgrown shrubs or those heavily damaged by animals. It is important to note that it may take a few years before spring flowering shrubs begin to bloom after rejuvenation pruning.
Take advantage of the cool weather and prune deciduous shrubs that are overgrown or have been damaged by animals, if they are not buried in snow, to bring them back to an aesthetically pleasing form.
If you have plant questions please call me at the University of Minnesota Extension office, Clay County at 218-299-5020, 1-800-299-5020 or email me at nels1657@umn.edu. Check out our website at www.extension.umn.edu/county/clay/