Frontier (elm hybrid)
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| Ulmus Frontier |
|---|
| Hybrid parentage |
| U. minor subsp. minor × U. parvifolia |
| Cultivar |
| Frontier |
| Origin |
| USA |
The American hybrid Frontier [1] is a U. S. National Arboretum introduction derived from a crossing of the European Smooth-leaved Elm U. minor subsp. minor with the Chinese Elm U. parvifolia in 1971, a unique example of the hybridization of a spring-flowering elm with an autumn-flowering species. Released in 1990, Frontier develops a vase or pyramidal shape, and glossy green foliage turning to burgundy in autumn. The ultimate height of the tree has yet to be determined, but should be in excess of 15 m. The tree rarely flowers, and has not produced seed. Reputed to have a high resistance to Dutch elm disease and elm yellows (phloem necrosis), it is only moderately resistant to elm leaf beetles. In trials in eastern Arizona [2], Frontier and another American hybrid Regal were found to have the highest tolerance of the hot and arid climate, notably exhibiting minimal leaf scorch. However, Frontier is known to have sustained winter damage where planted in the Great Plains [3].
The tree was included in 10-year trials at Atherton, California, to evaluate replacements for Californian elms lost to disease, and found to perform very well: "Strong structure, rapid growth rate, attractive leaf color in spring and fall, and relatively low pruning requirement suggest that Frontier has promise..." (Costello, 2004), although the tree again proved only moderately tolerant of elm leaf beetles. Frontier has had a limited introduction to Europe, where it is largely restricted to arboreta and elm collections; it also featured in trials in New Zealand during the 1990s at the Hortresearch station, Palmerston North.
Contents |
[edit] Arboreta etc. accessions
[edit] North America
- Bartlett Tree Experts acc. nos. 2001-097/8/9
- Holden Arboretum acc. no. 95-140
- Morton Arboretum acc. nos. 1284-2004, 433-2005
- Scott Arboretum acc. no. 91-242
- Smith College acc. no. 19804, 36005
[edit] Europe
- Brighton & Hove City Council, UK, NCCPG Elm Collection [4].
[edit] Nurseries
[edit] North America
- Backyard Trees, Park Hill, OK.
- Charles J. Fiore [5], Prairie View, Illinois
- ForestFarm [6], Williams, Oregon
- Herd Farm Nursery, Belvidere, TN.
- Jost Greenhouses, Missouri
- North American Plants [7], Lafayette, Oregon
- Pea Ridge Forest [8], Hermann, Missouri.
- Sunshine Nursery [9], Clinton, Oklahoma
[edit] Europe
None known.
[edit] Synonymy
None.
[edit] References
- Burdekin, D. A. & Rushforth, K. D. (Revised by Webber J. F. 1996). Elms resistant to Dutch elm disease. Arboricultural Research Note 2/96. Arboricultural Advisory and Information Service, Alice Holt, Farnham, UK.
- Costello, L. R. (2004). A 10 -year evaluation of the performance of four elm cultivars in California, U. S. Journal of Arboriculture, March 2004. [10]
- 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.
- Townsend, A. M., Schreiber, L. R., Masters, W. O. and Bentz, S. E. HortScience, 26: 80-81, 1991.
[edit] External links
- http://www.extension.iastate.edu/Publications/SUL4.pdf Summary, inc. photographs, of elm cultivars resistant to Dutch elm disease available in the USA.
- 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.
