Pruning Trees - When to Prune

Pruning your trees at the optimal time will speed the healing of the wound and reduce the stress on the tree. Generally, the best time to prune trees is when they are dormant. However, there are many exceptions to this rule depending on the type of tree and the type of branch you want to trim. Once you know when to prune, read up on how to prune too,

TIP: Our expert gardening advisor, Karen Thurber adds, "Avoid pruning trees in the fall. Trees that are pruned just before winter do not have sufficient time to heal before the cold weather sets in and will be more susceptible to winter injury."

Conifers

Your evergreen firs and pines may be pruned any time of year, but pruning during the dormant season may minimize sap and resin flow from cut branches.

TIP: Karen suggests, "Prune pine trees when the needles on the new growth, also referred to as candles, are not fully mature. Remove up to 2/3 the length of the candle."

Hardwood Trees and Shrubs

Prune these in the dormant season to easily visualize the structure of the tree, to maximize wound closure in the growing season after pruning, to reduce the chance of transmitting disease, and to discourage excessive sap flow from wounds.

Recent wounds and the chemical scents they emit can attract insects that spread tree disease. In particular, wounded elmwood is known to attract bark beetles that harbor spores of the Dutch elm disease fungus, and open wounds on oaks are known to attract beetles that spread the oak wilt fungus.

Take care to prune these trees during the correct time of year to prevent the spread of these fatal diseases. Contact your local tree disease specialist to find out when to prune these tree species in your area. Usually, the best time is during late winter just before the spring growth starts.

Flowering Trees and Shrubs

Trees and shrubs that flower in early spring (redbud, dogwood, etc.) should be pruned immediately after flowering (flower buds arise the year before they flush, and will form on the new growth).

Flowering trees susceptible to fireblight, including many varieties of crabapple, hawthorn, pear, mountain ash, flowering quince, and pyracantha, should be pruned during the fall or early winter. Fireblight is a bacterial disease that can be spread by pruning. Check with your county extension agent or a horticulturist for additional information.

Trees and shrubs that flower in the summer or fall always should be pruned during the dormant season (flower buds will form on new twigs during the next growing season, and the flowers will flush normally).

Dead Branches

These can be removed any time of the year.

TIP: Karen recommends, "Begin pruning and shaping your tree when it is young. Shaping your tree early will reduce the amount of required pruning as the tree ages. Removing small branches, rather than large branches, allows the tree to quickly heal and reduces the stress on the tree."