Prune in the late winter to encourage new growth in the spring. You want to prune at the end of winter or early spring before any new growth starts. Pruning late in the season before spring growth begins can prevent serious damage to your trees. Trees are. Prune apple trees, including flowering crabapples, mountain ash, hawthorns and shrub cotoneasters in late winter (February-early April).
Spring or summer pruning increases the 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.
Apr 05, When to Prune Ash Trees When to prune ash trees depends in part on why you are making the particular pruning cut. Unless you are pruning to remove dead and diseased branches, you should take care to prune in late winter, while the tree is still dormant. Most trees perform best when trimmed in the spring, according to University of Illinois Extension. Some trees, including oak, ash and elm, thrive with late summer or fall trimming. Ash trees should be trimmed in the fall.
Avoid trimming ash trees in the summer, when stressed ash trees prove most susceptible to the ash borer. Recommended Timing. To keep trees' health intact, the safest time to trim is during the late dormant season in winter, typically between the months of February and early April. Because deciduous trees are bare at this time of year, gardeners can easily see the branches to.