How to Care for an Elm Tree. The stately American elm tree was a popular shade tree before Dutch elm disease devastated it. American elms have a classic vase-shape, forming a canopy of shade. They were widely planted in urban areas because they are fast-growing and tolerant of compacted soils and air pollution. There are many species of elms that have replaced the classic American elm in the American landscape.
Choose elm tree varieties that provide better tolerance or resistance to Dutch elm disease. These include varieties of the American elm such as New Harmony, Valley Forge, Delaware and Washington and also the American Liberty elms. The Chinese or Lacebark elm is also more resistant to the disease.
Fertilize once or twice a year with a slow release nitrogen fertilizer. This will continue feeding the elm through the growing season. Look for one specifically for elms. Apply the fertilizer below the grass roots.
Prune in early spring once every three years, with minor pruning done every year. Cut as close as possible to the branch collar and the branch ridge without cutting into them. Large limbs require a small undercut a short distance away from the collar. Then make a clean top cut on the outside of the undercut.
Soak the ground outside the weeping or drip line with a hose to soak the tips of the roots. Allow the soil to dry in between watering. Water your elm when your lawn is yellowing, other trees like maples show signs of drought or your elm has wilting or browning leaves.
Dispose of dead limbs quickly. Burn the wood or, if you can't burn it, bury it. If you have a dead elm, remove the major limbs first and then cut the tree down. You may want to call a tree removal company.
Watch for and treat diseases and pests. The main diseases of the elm include Dutch elm disease, elm yellows and elm leaf black spot. Pests to watch for include the elm bark beetle, the elm leaf beetle and the elm leaf miner.
- The Chinese or Lacebark elm grows 40 to 60 feet and may be semi-evergreen in certain regions of the United States. These make excellent shade or lawn trees.
- Avoid standard lawn fertilizers. Nitrogen released quickly into the soil will cause weak new growth and may attract elm bark beetles.
- Never prune mid April to late July because open wounds attract the elm bark beetle. Also, don't prune in the fall because that is when fungal spores are most likely to be present.