When to Prune Trees and Shrubs: A Month-by-Month Guide

Pruning is the one landscape task where good intentions cause the most damage. A tree does not heal a wound the way an animal does; it walls the damage off and grows around it, which means every cut is permanent and the tree pays for it in stored energy. Timing determines how much it pays. Cut during dormancy and the wound closes quickly in spring with minimal pathogen exposure. Cut at the wrong moment and you invite disease, remove a season of flowers, or trigger a flush of weak growth just before winter. This guide sets out when to prune the trees and shrubs found in most North American yards, how to make a cut that closes cleanly, and where the line sits between homeowner pruning and work that belongs to a certified arborist.

When is the best time to prune a tree?

Late winter, from roughly February through early April depending on your region, is the best time to prune most deciduous trees. The tree is dormant, the branch structure is visible without leaves, insects and fungal pathogens are inactive, and the wound begins closing as soon as growth resumes in spring.

There are important exceptions. Maples, birches, and walnuts bleed sap heavily when pruned in late winter. The bleeding is not harmful to the tree, but if the appearance bothers you, prune those species in mid summer after the leaves have fully expanded.

Oaks are a genuine timing rule rather than a preference. In regions affected by oak wilt, oaks should never be pruned between April and July, when the beetles that spread the disease are active and drawn to fresh wounds.

Evergreens need very little pruning. Remove dead wood any time, shape spruces and firs in late winter, and prune pines by pinching the soft new candles in spring rather than cutting into old wood, which does not regenerate.

When should you prune flowering shrubs?

Prune spring-flowering shrubs such as lilac, forsythia, and azalea within a few weeks after they finish blooming, because they set next year's buds on old wood during summer. Prune summer-flowering shrubs such as panicle hydrangea, spirea, and rose of Sharon in late winter, since they bloom on new growth.

The simple rule is to ask when the shrub flowers. Blooms before roughly mid June means the buds were formed last year, so prune right after flowering. Blooms after mid June means the buds form on this year's growth, so prune while dormant.

Hydrangeas cause more confusion than any other shrub because the genus splits across both rules. Bigleaf and oakleaf hydrangeas bloom on old wood and should only be deadheaded, while panicle and smooth hydrangeas bloom on new wood and can be cut back hard in late winter.

Overgrown deciduous shrubs can be renewal pruned by removing one third of the oldest stems at ground level each year for three years. This rebuilds the plant without the bare, stubbed appearance that hard shearing produces.

Pruning windows by plant type

Plant type	Best time to prune	Reason
Most deciduous shade trees	Late winter, dormant	Visible structure, fast wound closure
Oak	November to March only	Oak wilt risk April through July
Maple, birch, walnut	Mid summer	Avoids heavy sap bleeding
Spring-flowering shrubs	Right after flowering	Buds set on old wood in summer
Summer-flowering shrubs	Late winter	Blooms on current season growth
Evergreen hedges	Late spring and midsummer	Two light shearings hold shape
Fruit trees	Late winter	Encourages fruiting spurs and open centre
Dead or hazardous wood	Any time	Safety takes priority over timing

How do you make a proper pruning cut?

Cut just outside the branch collar, the slightly swollen ring of tissue where the branch meets the trunk, without leaving a stub and without cutting flush into the trunk. The collar contains the cells that seal the wound, so preserving it is the single most important technical detail in pruning.

For any branch thicker than about an inch, use the three-cut method: an undercut a foot out from the collar, a top cut slightly beyond it to drop the limb, then a final clean cut at the collar. This prevents the falling branch from tearing bark down the trunk.

Never apply wound paint or sealant. Decades of research show it traps moisture and slows the tree's natural compartmentalization rather than helping it.

Keep tools sharp and clean. A clean cut closes far faster than a crushed one, and disinfecting blades between plants matters when working through material that may be diseased.