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Washington State University
WSU Puyallup Ornamental Plant Pathology


Study Objectives:
1. Determine the growth and horticultural performance of commercially available DED-resistant elm cultivars in various climate regimes in the United States.
2. Determine the relative disease, insect, and abiotic stress tolerance of these cultivars.
3. Promote the propagation and use of elms through local, regional, and national reporting of the trial results to wholesale tree propagators and growers, retail nursery and garden center operators, landscaper designers, arborists, and the general public.


1. In 2005, fourteen elm cultivars were planted in various locations in the United States.
2. Each cultivar is represented by one tree in each of five blocks in a randomized complete block.
3. The elm cultivars represent a range of hybrids and species of Ulmus commercially available.
4. The trial will be conducted over a period of 10 years.
5.Using a standard format, annual assessment of each tree will include: height, diameter, crown characteristics, and fall color. At appropriate times during each year, each tree will also be assessed for response to vascular diseases, canker diseases, foliar diseases, scale insect infestations, foliar-feeding insect infestations, bark beetle infestations, and abiotic damages (frost/freeze, wind, winter dieback, sunscald, and insufficient soil moisture).

WSU plot map

Ice damage from January 2012 storm