The late dormant season is the best time for most pruning.
Prune to promote plant health Remove dead or dying branches injured by disease, severe insect infestation, animals, storms, or other adverse mechanical damage. Pruning shrubs in Minnesota is similar to pruning in any other US Department of Agriculture hardiness zone.
Regardless of the species or variety of your shrubs, determining the best time to prune them depends on when they bloom. Early-Spring-Blooming. Nearly all shrubs that bloom in very early spring do so on wood grown the previous summer. There are other factors that will determine when a tree should be pruned. Generally, shrubs and trees that bloom on new growth should be pruned in the late winter and early spring, while those that bloom on old growth should be pruned in late spring or summer.
Evergreen Shrubs. Prune evergreen shrubs, such as juniper and yew, in late March or early April before new growth begins. Light pruning may also be done in mid-summer. Avoid pruning evergreen shrubs in the fall. Fall pruned evergreens are more susceptible to winter injury. Deciduous Trees.
February through March is generally regarded as the best time to prune most deciduous trees. A lot of homeowners request pruning services in the fall as part of an overall effort to clean up their landscape before the winter and this can certainly be performed on many shrubs.
Pruning bushes around the home can help them look shapely and nice before visitors come for.