Ulmus 'Morton Stalwart'
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| Ulmus hybrid |
|---|
| Hybrid parentage |
| 'Morton' (Accolade™) × (U. pumila × U. minor). |
| Cultivar |
| 'Morton Stalwart'
Commendation™ |
| Origin |
| USA |
The elm hybrid cultivar 'Morton Stalwart' (Commendation™) is a Morton Arboretum selection, derived from a controlled crossing of the 'Morton' (Accolade™) hybrid with a crossing of the Siberian Elm Ulmus pumila and a selection of Field Elm Ulmus minor from eastern Russia [1] [2].
'Morton Stalwart' (Commendation™) is reputedly vigorous and robust, adjudged the third fastest-growing cultivar of 17 assessed by the University of Minnesota; it is also extremely tolerant of drought [3] and cold. In artificial freezing tests at the Morton Arboretum [4] the LT50 (temp. at which 50% of tissues die) was found to be - 40 °C.The branches are upright, but the form of the tree is ultimately more oval than vase-shaped.
However, its performance in the southern United States has not impressed, and it was dismissed, along with its Morton stablemates 'Morton Glossy' (Triumph™) and 'Morton Plainsman' (Vanguard™), as "ugly" by Michael A. Dirr, Professor of Horticulture at the University of Georgia [2], on account of its "wild" growth and splaying branches. Moreover, the relatively large leaves are fairly susceptible to attack by insects, notably elm leaf beetle, Japanese beetle and Gypsy moth. The tree is currently being evaluated in the National Elm Trial [3] coordinated by Colorado State University.
'Morton Stalwart' is being promoted by the ChicagolandGrows corporation; it has not been introduced to Europe or Australasia.
Contents |
[edit] Arboreta etc. accessions
- North America
- Arnold Arboretum acc. no. 131-2002
- Bartlett Tree Experts acc. nos. 2003-370, 2003-371, 2004-329, 2004-339.
- Bickelhaupt Arboretum acc. no. 02-018
- Chicago Botanic Garden, Glencoe, Illinois. 1 tree, planted in the Parking Lots; no other details available.
- Dawes Arboretum [4], Newark, Ohio. 2 trees, no acc. details available.
- Holden Arboretum acc. no. 00-124
- Morton Arboretum acc. nos. 274-97, 109-2006
- Smith College acc. no. 36405
[edit] Nurseries
- North America
- Acorn Farms [5], Galena, Ohio
- J. Frank Schmidt & Co. [6], Boring, Oregon
- Willoway Nurseries [7], Avon, Ohio
[edit] References
- ^ Santamour, J., Frank, S. & Bentz, S. (1995). Updated checklist of elm (Ulmus) cultivars for use in North America. Journal of Arboriculture, 21:3 (May 1995), 121-131. International Society of Arboriculture, Champaign, Illinois, USA.
- ^ Warren, K., J. Frank Schmidt & Son Co. (2002). The Status of Elms in the Nursery Industry in 2000 [1]
- ^ Giblin, C. P. & Gillman, J. H. (2006). Elms for the Twin Cities: A Guide for Selection and Maintenance. University of Minnesota.
- ^ 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.
