Elms: A Tree Under Threat Begins its Recovery
Take this virtual tour to explore the journey of elm trees as we present their threats and the dedicated efforts to save them!
Street trees in suburban Chicago (2015) by The Morton ArboretumThe Morton Arboretum
Why elms?
The elm's utility as a shade tree has led to its popularity in the urban landscape. The American elm (Ulmus americana) was once very common along streets because of its rapid growth, vase-like shape, and adaptation to a variety of climates and soils.
Studying Dutch Elm Disease (1955/1959) by The Morton ArboretumThe Morton Arboretum
Threats to elms
DED (Dutch elm disease) is caused by a fungus called Ophiostoma ulmi that was introduced to the United States in the 1930s. DED has devastated elm populations across the country.
Dutch Elm Disease in Riker Mount (1960/2000) by The Morton ArboretumThe Morton Arboretum
The American elm is extremely susceptible and the disease has killed hundreds of thousands of elms across the country.
The disease is most easily detected during early summer when the leaves on an upper branch curl and turn gray-green or yellow and finally brown.
There are two insect vectors responsible for transmitting DED: the native elm bark beetle and the European elm bark beetle. These beetles lay their eggs in infected trees. When the adult beetles emerge, they carry the fungus with them when they travel to healthy trees.
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The Elm Collection at The Morton Arboretum
The Morton Arboretum in Lisle, Illinois, has one of the most extensive collections of elm family plants (Ulmacea) in the world.
Sunday traffic heading to west side showing west entrance road, near Elm Collection (1960s) by UnknownThe Morton Arboretum
The Elm Collection was started in 1926, making it one of the world's oldest taxonomic collections. It covers more than five acres near the main entrance at the Arboretum. Many of the 167 specimens are mature, spreading shade trees.
How The Morton Arboretum is helping
The Elm Collection is an integral part of the tree breeding program at The Morton Arboretum. Years of research and testing led to the introduction of several elm cultivars resistant to Dutch elm disease.
Through the Chicagoland Grows Plant Introduction Program, the Arboretum has successfully introduced five new elm cultivars which have enabled the elm trees' return to the landscape.
These elms include Accolade elm (Ulmus 'Morton'), Triumph elm (U. 'Morton Glossy'), Vanguard elm (U. 'Morton Plainsman'), Danada Charm elm (U. 'Morton Red Tip'), and Commendation elm (U. 'Morton Stalwart').
CHANGE bench in the maple (Acer) collection at The Morton Arboretum (2013-06-11) by The Morton ArboretumThe Morton Arboretum
Join The Morton Arboretum in championing elms and other tree species around the world. Learn more about The Morton Arboretum's work at mortonarb.org
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