Timing for Late Pruning Trees

Timing For Late Pruning

The late dormant season is best for most pruning. Pruning in late winter, just before spring growth starts, leaves fresh wounds exposed for only a short length of time before new growth begins the wound sealing process. Another advantage of dormant pruning is that it’s easier to make pruning decisions without leaves obscuring plant branch structure. Pruning at the proper time can avoid certain disease and physiological problems:

Pruning at the proper time can avoid certain disease and physiological problems:

  • To avoid oak wilt disease DO NOT prune oaks from April to October. If oaks are wounded or must be pruned during these months, apply wound dressing or latex paint to mask the odor of freshly cut wood so the beetles that spread oak wilt will not be attracted to the trees.

  • To avoid increased likelihood of stem cankers, prune honeylocusts when they are still dormant in late winter. If they must be pruned in summer, avoid rainy or humid weather conditions.

  • Prune apple trees, including flowering crabapples, mountain ash, hawthorns and shrub cotoneasters in late winter (February-early April). Spring or summer pruning increases chances for infection and spread of the bacterial disease fireblight. Autumn or early winter pruning is more likely to result in drying and die-back at pruning sites.

  • Some trees have free-flowing sap that “bleeds” after late winter or early spring pruning. Though this bleeding causes little harm, it may still be a source of concern. To prevent bleeding, you could prune the following trees after their leaves are fully expanded in late spring or early summer. Never remove more than 1/4 of the live foliage. Examples include:

    • All maples, including box elder

    • Butternut and walnut

    • Birch and its relatives, ironwood and blue beech

 

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