Lovely with reddish buds that open to snow white flowers in spring, the Snowdrift crab apple (Malus 'Snowdrift') is a rounded, densely branching small tree that begins small but will mature to a height and width of 15 to 20 feet. This selection is resistant to many common diseases that afflict crab apples; the rare need for pruning is for removal of dead or broken branches or occasional shaping. To prevent diminishing the floral display, prune after flowering ends and then only lightly to allow for even and attractive re-growth of twigs.
Examine the crab apple. Look for dead or broken branches or twigs that were damaged during the winter. Dead branches are lighter in color, do not bend and often have bark that is dry and flaked away.
Trim off these dead and damaged branches 1/4-inch above a living branch crotch or 1/4-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 or early spring before buds swell and open.
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 bases with a clean cut that does not lead to a tear-back of bark onto the trunk.
Re-examine the canopy of the crab apple. Look for criss-crossing 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. Again, make cuts 1/4-inch above a lower branch junction or dormant bud.
Tip prune any branch that is awkwardly growing outward from the canopy, detracting from the overall rounded shape. Make cuts 1/4-inch above their attachment to a branch crotch or 1/4-inch above a dormant bud.