There are at least three hundred named varieties of crab apple trees. It is one of the most popular trees planted in urban areas. In spring crab apples produce white, pink or red flowers. Small fruits form in summer, ripening in fall to tiny red apples. Many varieties of crab apple trees keep their fruit on the trees well into the winter months. Prune crab apple trees in early spring every year to keep them well-shaped and healthy enough to produce lots of fragrant blossoms and tiny apples.
Remove dead, diseased or broken branches. Cut them back all the way to the main trunk. Make the cut about an inch from the point where it grows out from the main trunk. Angle the cut slightly downward. This will help keep water from collecting in the small stub, which could invite disease or insects to take up residence.
Remove any branch stubs growing along the trunk below the canopy.
Remove any "water spouts." These are vigorous branches that grow straight up from the lateral branches.
Prune out any suckers. These are upright branches that grow up from the ground at the base of the tree trunk.
Take out any branches that rub against or cross over another branch. This is important because rubbing branches can rip the bark and open up the tree for insects or disease to enter.
Cut off any branches that are growing out from the main trunk at less than a 45 degree angle.
Prune off branches that are growing too close to another branch. Of the two, remove the branch that forms the smallest angle growing out from the main trunk.
Cut up to one-third of the new growth at the end of the lateral branches. This will encourage it to produce more fruiting branches along its length. The bark of new growth will be slightly lighter in color than older growth.