Apple trees (Malus domestica and other species) benefit from pruning in many ways. Pruning apple trees makes them better able to support the weight of the fruit, produces higher quality fruit and makes it easier for fungicides and insecticides to penetrate the tree’s canopy. Unfortunately, many gardeners choose to prune their apple trees from the autumn, which can be among the worst times to harden apples. Apples trees should be pruned in late winter or early spring for best results. Fall pruning can lead to many unintended effects and have a negative effect on tree health.
Like all plants, apple trees collect carbohydrates, nitrogen and other nutrients that they need from both the dirt and the photosynthesis occurring in the leaves. The tree distributes these nutrients as required during the growing season. To conserve nutrients and store them for another growing season, the tree goes nutrients out of the canopy and in the roots and trunk for winter. This allows the tree to maintain a constant energy level during winter dormancy and fast move nutrients back in the canopy when required for spring development. Fall pruning interrupts this flow of nutrients, removing parts of the tree canopy prior to the nutrients are moved elsewhere in the tree. This makes the tree work harder to generate new growth in the spring, potentially reducing both yield and total tree health.
Although beneficial to the tree in many ways, pruning a tree actually inflicts harm on it. Pruning causes a wound that the tree heals by making new development at the website or, in the case of rather massive limbs, scabbing over. Fall is a time when apple trees ought to be preparing for dormancy, not creating new development which won’t have time to harden off before chilly winter temperatures arrive. All the tender new development generated by the apple tree after a drop pruning will die or endure cold weather damage. Dead and broken limbs won’t continue to grow and grow properly and won’t fruit.
The fungus, bacteria and insects which occasionally infect apple trees are all living things which seek out a spot spend the chilly winter season. Regrettably, fresh cuts on an apple tree supply them with an easy entrance into the tree where they may survive the winter and have a ready food supply in the spring once the tree starts to climb again. Once established, some diseases can be very hard to treat and may alter the quantity and quality of the fruit produced by the tree. Pruning later in the season gives the tree a chance to heal before warm weather reawakens fungus, bacteria and insects.
What Can Be Done
Although apple trees shouldn’t be pruned in the fall, there are some things which you can do to promote the health of your tree. One is to rake up any fallen fruit and leaves from beneath the tree and dispose of them. It is also a good idea to rake up any old mulch and replace it with fresh. Just as bacteria and fungus may overwinter in the apple tree, then they are also able to hide in fallen leaves and rotten fruit which aren’t cleaned up prior to winter. Dead limbs can be removed from apple trees in the autumn so long as you don’t cut into any living wood when removing them.