The slippery elm is a fast-growing deciduous tree, which is hardy in zones 3 to 9. A mature tree can reach 60 feet tall with a spread of 50 feet.The tree is vase-shaped and does well in full sun to partial shade. Unlike the American elm, the slippery elm's branches appear higher on the trunk, and it has fewer main branches. It is susceptible to Dutch Elm disease.
Prune the slippery elm for the following reasons: to remove diseased or damaged branches, to keep the tree within its space in your landscape, for safety reasons (walkways, buildings, and roofs) and to open up the crown of the tree. The type of pruning tool will depend upon the size of the branch or limb, and its location.
Prune away damaged or diseased branches or limbs as soon as possible, making a clean cut. It is important to make a clean cut and avoid any additional damage to the bark of the tree (if the break is close to the trunk). You can do this any time of the year. Damaged or broken branches provide an entry for disease, so it is best to prune them right away.
Prune to maintain size or ensure safety by cutting off the problem branches. Find the branch collar on the underside of the branch where it connects to the trunk, and the branch bark ridge on the topside of the branch where it connects to the trunk. Make your cut in front of the branch bark ridge and the branch collar. Be careful not to cut into the branch collar or branch bark ridge. Do not leave a stub. This can be done in early spring or late fall when the tree is dormant.
Perform a visual inspection of the crown to determine if the tree needs thinning. Thinning of the crown refers to the removal of any dead wood, including twigs, branches, and limbs, and also the removal of any cross-over branches. This kind of pruning usually is done by professional tree services.They also are knowledgeable as to what branches to cut to maintain the health, integrity and appearance of the tree.