The weeping "Louisa" flowering crabapple (Malus "Louisa") brightens your landscape with its red spring buds that open into fragrant, pink flowers. The woody, bloom-covered branches droop downward, adding a flowing element to keep your eye in constant motion. Hardy in U.S. Department of Agriculture plant hardiness zones 4 through 8, the "Louisa" crabapple prefers full sunlight and fertile, fast-draining, sandy loam soils. Help your "Louisa" crabapple stay healthy and remain a vigorously blooming, nicely shaped part of your landscape with annual trimming in the spring, right after it's done blooming.
Pour 1 part bleach and 9 parts water into a bowl or bucket. Submerge the blades of your pruning shears, loppers and pruning saw in the solution. Leave the blades to soak for at least 5 minutes to sterilize the tools. Blot the blades dry with a cloth.
Put on a pair of gloves to protect your hands from scrapes or cuts during the pruning process. Clear any objects, large rocks and other obstacles from the ground beneath the weeping "Louisa" crabapple tree to eliminate the danger of tripping or stumbling while you work around the tree.
Cut out any dead branches that have become dry or remain leafless. Use the pruning shears to cut through branches with diameters of 1/4 inch or less, loppers for diameters 1 1/2 inches or less, and a pruning saw for branches 1 inch or greater. Make each cut 1/4 inch above the swollen ring of tissue, known as the branch bark collar, surrounding the branch's base.
Prune out any broken, cracked or split branches from the "Louisa" crabapple's canopy. Cut through the branch 1/4 inch above an outward-facing lateral branch, leaf or bud that's 1 to 2 inches below the damaged portion.
Trim away any suckers, or new shoots growing from the trunk or surrounding ground. Slice through each sucker as close to its bottom as possible without cutting or damaging the tree's trunk to completely remove it.
Cut out any thin, vertical, vigorously growing branches that produce minimal flowers -- known as watersprouts -- from the tree's canopy. Cut through the base of each watersprout 1/4 inch above the point where it joins with the tree's trunk or another branch.
Trim away any branches that cross or rub against another limb. Cut 1/4 inch above the branch bark collar, an outward facing lateral branch or bud.
Cut out any severely diseases branches that contain spotted, dead, infested or falling leaves. Make the cuts in the same manner as before. Sterilize the pruning tool in the 10 percent bleach solution after each cut to prevent spreading the disease.
Cut out or remove any vigorously growing limbs that detract from the "Louisa" crabapple's overall appearance. Remove one branch less than 1 inch in diameter in each crowded portion of the canopy to thin the tree and allow additional sunlight and air into the space.