Elms are making a comeback on our city streets. Once the most widely planted of urban trees, American Elms were nearly wiped out by the introduction Dutch Elm Disease (DED) to North America. Over the past two decades, various DED-resistant cultivars have been developed via hybridizing and selection. A number of surviving American Elms have been tested and proven disease resistant. Which ones are best?
A national elm evaluation trial is underway that will help determine the best cultivars for your market area. In 2005, J. Frank Schmidt & Son Co. contributed more than 1,000 young bare root trees of the many cultivars we grow. These were planted in large replicated trials at 18 trial sites in 17 states that represent a wide range of climate zones, soils and other environmental conditions. Additional cultivars were added in 2006 and 2007, bringing the total number to 20 cultivars for which performance is being measured by a team of land grant university scientists and extension specialists.
Sites are located in these states: Alabama, California, Colorado, Indiana, Iowa, Kansas, Kentucky, Michigan, Minnesota, New Jersey, New York, North Dakota, Ohio, Utah, Vermont, Washington and West Virginia.
Using a standard format, the evaluation team measures each tree for height, diameter, crown characteristics and fall color. At appropriate times throughout the year, each tree is assessed for response to vascular, canker and foliar diseases. Scale insect, bark beetle, and foliar-feeding insect infestations are also measured. Abiotic damages caused by frost/freeze, wind, winter dieback, sunscald and insufficient soil moisture are observed and reported to the central coordinating office at Colorado State University. Ongoing results, progress reports, photographs, and related news articles are posted on the university’s Forest and Shade Tree Health Lab website.
We urge you to visit the elm trial plot in your region and see for yourself which ones are shaping up to be top performers. Contact information for each location is posted on the National Elm Trial website.
Elms on parade at
J. Frank Schmidt & Son Co.
Most of the National Elm Trial cultivars are also growing and thriving in two landscape settings at our nursery.
The J. Frank Schmidt Jr. Arboretum provides a beautiful park-like environment for the elms. The oldest are approaching mature form after 20 years in the landscape.
A more recent planting, dividing the expanses of gravel of employee parking lot and our loading dock staging area, is already casting cool shade on employee vehicles. Planted in single file in 2005, the 10 cultivars of American and hybrid elms are identified by Latin and common names and serve as a living laboratory for observation and comparison.
See the chart below for photos and information on the cultivars in our parking area.
Ten elm cultivars shade the gravel parking lot adjacent to the shipping dock at our headquarters in Boring.