Ulmus 'Morton Plainsman' = Vanguard
|Ulmus 'Morton Plainsman'|
|Hybrid parentage||U. pumila × U. davidiana var. japonica|
|Cultivar||'Morton Plainsman' = Vanguard™|
Ulmus 'Morton Plainsman' (selling name Vanguard™) is a hybrid cultivar raised by the Morton Arboretum from a crossing of Siberian Elm (female parent) and a Japanese Elm grown from openly pollinated seed donated by the Agriculture Canada Research Station at Morden, Manitoba.
Vanguard has modest upright growth, increasing in height by an average of 0.8 m in an assessment at U C Davis, with leaves much the same size and colour of the American Elm.  However, its performance in the southern United States has not impressed, and it was dismissed, along with its Morton stablemates Commendation and Triumph, as "ugly" by Michael Dirr, Professor of Horticulture at the University of Georgia , on account of its "wild" growth and splaying branches.
Pests and diseases
In trials at the University of Minnesota, Vanguard was found to have the second highest (after Danada Charm) incidence of branch breakage occasioned by bark inclusions. However, the tree has a high degree of drought and cold tolerance making it particularly suitable for afforestation in the Great Plains. In artificial freezing tests at the Morton Arboretum  the LT50 (temp. at which 50% of tissues die) was found to be -40°C.
- North America
- Bartlett Tree Experts, US. Acc. nos. 2001-106, 2001-108
- Brenton Arboretum, US. 5 trees, acquired 2009. Acc. no. not known.
- Chicago Botanic Garden, US. 2 trees, no other details available.
- Dawes Arboretum , US. 3 trees, no acc. details available.
- Holden Arboretum, US. Acc. no. 00–127
- Morton Arboretum, US. Acc. nos. 273–97, 4–2004, 156–2005.
- Smith College, US. Acc. no. 36505
- University of Idaho Arboretum, US. Two trees. Acc. no. 2000093
- North America
- Acorn Farms , Galena, Ohio, US.
- Bailey Nurseries , St. Paul, Minnesota, US.
- J. Frank Schmidt & Son , Boring, Oregon, US.
- Johnson's Nursery , Menomonee Falls, Wisconsin, US.
- Sun Valley Garden Centre , Eden Prairie, Minnesota, US.
- McPherson, G. et al. (2008). National elm trial: Initial report from Northern California. Western Arborist, Fall 2009, 32–36.
- "Elm Leaf Beetle Survey". Archived from the original on 2011-07-19. Retrieved 17 July 2017.
- Brady, C., Condra, J., & Potter, D. (2008) Resistance of Landscape-suitable Elm (Ulmus spp.) Cultivars to Japanese Beetle, Leaf Miners, and Gall Makers. 2008 Research Report, Nursery & Landscape Program, 15–16. University of Kentucky.
- Giblin, C. P. & Gillman, J. H. (2006). Elms for the Twin Cities: A Guide for Selection and Maintenance. University of Minnesota.
- Santamour, Frank S.; Bentz, Susan E. (May 1995). "Updated Checklist of Elm (Ulmus) Cultivars for use in North America". Journal of Arboriculture. 21 (3): 122–131. Retrieved 20 June 2016.
- Ware, G. (1992). Morton. Arb. Quarterly 28(1): 1–5, 1992.
- Shirazi, A. M. & Ware, G. H. (2004). Evaluation of New Elms from China for Cold Hardiness in Northern Latitudes. International Symposium on Asian Plant Diversity & Systematics 2004, Sakura, Japan.
- http://fletcher.ces.state.nc.us/programs/nursery/metria/metria11/warren/elm.htm Warren, K., J. Frank Schmidt & Son Co. (2002). The Status of Elms in the Nursery Industry in 2000.
- http://www.mortonarb.org/plantinfo/plantclinic/phc/New-Elms-For-The-Landscape.pdf. Miller, F. (2002). New elms for the landscape and urban forest.