Landscape Plants of the Upper Midwest

American Elm

{Picture of American Elm}
Picture

Plant Information

  • Plant Type: Tree: Large
  • Scientific Name: Ulmus americana
  • Family: Elm
  • Related Cultivars:

    Ulmus americana `New Harmony'
    Ulmus americana `Valley Forge'
    Ulmus americana `Princeton'

  • Zone: 5
  • Plant Size: 70-80'
  • Bloom Time: Spring
  • Culture:

    Highly adaptable to almost any soil. Very tolerant of urban conditions. Full sun.

  • Notes:

    The American elm’s graceful, vase-shaped branching once formed magnificent cathedral-like ceilings along city streets throughout much of the U.S.  Dutch elm disease, first identified in the U.S. around 1930, killed most of these trees during the middle part of the twentieth century. Fortunately, researchers have identified a number of cultivars that are tolerant of Dutch elm disease, which are now available in the nursery industry. All of the cultivars listed here have been tested and found to be very tolerant of the disease. Once again, this stately tree can legitimately be considered when planning landscapes, especially in difficult soils and urban settings.

  • Pruning:Pruning animation

    Structural pruning targets branch defects with the goal of producing strong-branched, long-lived trees with a low risk of storm damage.  The importance of addressing branch defects when trees are young cannot be over-emphasized. The suppression or removal of small branches is far easier and better for long-term tree health than when branches become large.  Beginning when a tree is planted, it should be evaluated each year and branches with structural defects should be suppressed, or if small, removed.  This will promote a resilient tree structure that is also more ascetically pleasing.    

    These site explain the fundamentals of structural tree pruning:

    Urban Tree Foundation – Structural Pruning

    University of Florida – Structural Pruning

    If a branch needs to be removed for clearance, is damaged, or possesses a critical defect, a 3-point cut is used (see animation). First an undercut is made to prevent bark from tearing down the trunk if it remains attached to the falling limb. The branch is then "stub cut" which removes most of the branch to facilitate a clean final cut. The final cut is made just outside the branch collar, which is the swollen area between the branch and the trunk. Cuts made here will heal most readily and prevent rot from invading the main trunk of the tree, a common occurrence when branches are cut flush with the trunk.

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Landscape Plants of the Upper Midwest
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Contact
Bill Hoch, Associate Professor
Montana State University
E-mail: bhoch@montana.edu

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