Why We Prune Trees, Shrubs, and Vines
- Plant health and safety | Removal of dead, damaged, or diseased, or overlapping branches, buds, or roots, as well as suckers and water sprouts assists with plant health (strength, air circulation, sun reach, and pest and disease resistance) and appearance.
- Control size and shape | Pruning can improve the plant structure in addition to allowing better air and light conditions.
- Stimulate new growth | Pruning encourages new growth.
Always prune for a specific reason, not because you think you should do it.
Pruning Principles 101
In general, the principle is, prune when the plant is asleep (dormant) and does not have buds.
The best time for pruning most trees, shrubs, and vines (if they do need pruning) is late winter and early spring unless they are early spring bloomers and already have buds.
The second-best time is summer. After flowering is the best time for spring bloomers.
Avoid fall. Pruning stimulates new growth and you don’t want this with winter on its way.
Dead, damaged, and diseased branches can be removed any time.
Trees and Shrubs
- Deciduous trees, evergreens, and non-coniferous shrubs handle pruning best in mid-winter when the sap is not running.
Avoid the heavy sap flow time in spring for trees like walnut and maple (and other trees you can tap for syrup).
- The key for pruning flowering and fruiting trees and shrubs is to know when the plant fruits and whether it produces the fruit on old or new wood/growth.
The goal when pruning is to remove the old (and no longer useful or flowering wood) while protecting whatever parts are creating new flower and fruit buds.
Other Garden Perennials
- Many flowering perennials are best cut back (removing old, dead growth) in spring just as the new growth starts poking up.
While you could do this in the fall, you would be removing valuable winter food and habitat for wildlife (from microbes to birds and more), so wait if you can.
- Trimming herbaceous growth like leaves on a boxwood hedge is done during the growing season (ending weeks before first frost).