One of the most glorious spring flowering trees is the crab apple (Malus spp.). Best grown in regions with cold winters, this plant comes in a wide selection of flower colors, fall foliage tones and tiny fruit colors. In general, crab apple is a small tree with minimal annual pruning maintenance. Occasional pruning in late winter to remove sprouting twigs, crisscrossing or rubbing branches or irregularly long branches ensures the tree looks its best. Dead, damaged or diseased wood can be pruned away at any time.
Schedule pruning the crab apple at the end of its winter dormancy for best recovery from pruning. Late winter or early spring is perfect, such as late February to early April, when the leaf and flower buds have not yet swollen or opened.
Examine the tree. Look for dead or broken branches or twigs that occurred during the winter. Dead branches are lighter in color, do not bend and often have bark that is dry and flaked away. Also choose to remove web cocoon sacs of insects that are wrapped around clusters of twigs. Cut away the entire stem or twigs carrying the web sac.
Trim off these dead and damaged branches a quarter inch above a living branch crotch or a quarter inch above a dormant bud. If branches die or are damaged and diseased, they can be pruned away any time of year, not just in late winter.
Spray the pruners or lopper blades with the rubbing alcohol after cutting diseased branches. The solution sterilizes the blades and reduces the chance of inadvertently spreading pathogens from branch to branch as you prune.
Remove suckers from the base of the tree trunk or along its length. Suckers are weak sprouts that add no structural interest to the tree but do require energy that could be better utilized for the leaves and flowers in the main canopy of the crab apple. Cut suckers at their base with a clean cut that does not lead to a tear-back of bark onto the trunk.
Again spray the pruners or lopper blades with the alcohol solution after pruning on the different areas of the tree.
Refocus efforts on the canopy of the crab apple. Look for crisscrossing branches or those that are rubbing against each other. Trim away branches or twigs in these situations so that one healthy branch remains after the pruning.
Tip prune any branch that is awkwardly growing outward from the canopy, detracting from the overall rounded shape. Make cuts a quarter inch above its attachment to a branch crotch or a quarter inch above a dormant bud.
Monitor the crab apple tree during the growing season. Prune away diseased foliage or branches whenever encountered, always making sure the cut is a quarter inch above a dormant bud or healthy branch junction. Sterilize the pruner's blades after each cut on diseased items.