Prairie Expedition® American Elm -- Ulmus americana ‘Lewis & Clark' (RFM-37)

prairie expedition

Excellent cold hardy Dutch Elm Disease (DED) resistant American elm selection. The original tree was a lone survivor among other American elm trees that died from DED. Released and named in honor of the 200th anniversary of the Lewis and Clark Expedition in 2004.


USDA hardiness zone 3-9

Mature Size:

Height: 60', Spread: 40'

Form (Shape):

Umbrella-like form which typifies American elm.

Growth Rate:

Medium to Fast; NDSU trials averaged 3 – 4’ of growth annually over 10 years of evaluation.


Alternate, Simple, 3 – 6” long and 1 – 3’ wide;  Summer: High quality lustrous dark green; Autumn: Yellow




Greenish-red fascicles of 3 – 4 (perfect), not showy


Rounded disc-shaped samara, not ornamental

Special Features:

DED resistant

Light Preference:

Full sun exposure

Soil Preference:

Prefers rich, moist soils but is highly adaptable to different soil types and pH.


Softwood stem cuttings

Ornamental Attributes;

High quality summer foliage.

Landscape Attributes:

Prairie Expedition® is an outstanding DED resistant American elm selection. Uses for this cultivar are in boulevard, park plantings and other large open spaces.


Clonal trees were inoculated with DED and shown to be resistant to the disease. The original tree (pictured above) has a double leader, which makes the tree wider than what it would be if properly maintained as a single leader in the landscape.

Patent Status:

U.S. Trademark registered – Prairie Expedition®

Canadian Trademark registered

Licensing Status:

This cultivar is available for non-exclusive licensing.


Download the PDF Datasheet (PDF, 268.07 KB)

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