WSU Puyallup Ornamental Plant Pathology
Pruning Elm Trees
The irrigation system should be turned OFF in early September to allow the trees to harden-off before the onset of cold winter temperatures; this will reduce winter kill.
Prune after the trees have dropped their leaves … late fall, winter, early spring.
- Remove all dead branches.
- Remove or reduce co-dominant branches … if there are parallel branches remove the one closest to the main stem … prune so that the crown is balanced on all sides.
- IF there is no obvious leader, select one upper branch to become the leader, remove all other nearby competing branches.
- IF a leader already exists, reduce the size by 1/3 – 1/2, and remove all the small branches within 6″-12″ of the tip of the leader.
- For cultivars that have close-spaced branches along the main stem, remove every other branch along the stem to open up the crown.
- Remove all branches that are growing towards the main stem … new growth should be away from the main stem.
- Remove all branches on the lower 1/3 – 1/2 of the tree, however, in the case of trees with very small diameter main stems, do not completely remove all of the lower branches, but rather, prune them back by 1/2 their length … this will help to develop caliber during next year’s growing season.
- DO NOT secure the trees to stakes or poles during the winter … wait until spring to do this.
WSU Puyallup Research & Extension Center, 2606 West Pioneer, Puyallup, WA, 98371-4998 USA
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