Ulmus americana 'Lewis & Clark' = Prairie Expedition | |
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Species | Ulmus americana |
Cultivar | 'Lewis & Clark' |
Marketing names | Prairie Expedition |
Origin | North Dakota State University Research Foundation, US |
The American elm cultivar Ulmus americana 'Lewis & Clark' (trade name Prairie Expedition) is a development from the North Dakota State University (NDSU) Research Foundation breeding programme, released in 2004 to commemorate the 200th anniversary of the eponymous expedition. [1] The cultivar was cloned from a tree discovered in 1994 along the Wild Rice River south west of Fargo, North Dakota, where all those around it had succumbed to Dutch elm disease; the tree remains in perfect health (2008). Prairie Expedition proved only moderately successful in the US National Elm Trial, averaging a survival rate of 62.6% overall, potentially due to environmental factors rather than susceptibility to Dutch elm disease. [2] Nevertheless, Prairie Expedition is considered the hardiest of the American Elm cultivars, able to survive in Zone 3 (-40 to -34 Celsius). [3]
Prairie Expedition was introduced to the UK in 2008 by Hampshire & Isle of Wight Branch, Butterfly Conservation , as part of an assessment of DED-resistant cultivars as potential hosts of the endangered White-letter Hairstreak. [4]
Prairie Expedition is distinguished in maturity by its broad umbrella crown and dark green foliage. [5] However, the tree was judged to have little ornamental value in the National Elm Trial . [3] The clone grows moderately quickly, averaging an increase of > 1 m in height per annum when young, reaching a height of <17 m in 25 to 30 years. [6] The leaves are < 13 cm in length by 9 cm broad, coarsely-toothed, and with a 4 mm petiole.
Possession of an innate resistance to Dutch elm disease was suggested after inoculation with the causal fungus at the NDSU, [7] however replication of the tests is considered too limited to be conclusive. No other specific information available, but the species as a whole is highly susceptible to Elm Yellows; it is also moderately preferred for feeding and reproduction by the adult Elm Leaf Beetle Xanthogaleruca luteola , [8] and highly preferred for feeding by the Japanese Beetle Popillia japonica [9] [10] in the United States. U. americana is also the most susceptible of all the elms to verticillium wilt. [11] [10]
Prairie Expedition has been included in the National Elm Trial coordinated by Colorado State University. The tree is in commerce in the US, and was introduced to the UK from Canada by Butterfly Conservation in 2008, [4] and thence to the Netherlands in 2010.
The tree is named for the Lewis and Clark Expedition of 1804.
The American elm cultivar Ulmus americana 'Augustine', originally called 'Augustine Ascending', was cloned by Archie M. Augustine of the Augustine Nursery of Bloomington, Illinois, from a nursery seedling planted in 1927 in Normal, Illinois, and found to be columnar in habit.
The American Elm cultivar Ulmus americana 'Independence' was raised by Eugene B. Smalley and Donald T. Lester at the University of Wisconsin–Madison from a crossing of the American Elm cultivar Moline and American Elm clone W-185-21, to become one of the six clones forming the American Liberty series, and the only one to be patented.
The American Elm cultivar Ulmus americana 'Valley Forge' was raised by the Agricultural Research Service in Maryland. The tree was released to wholesale nurseries without patent restrictions by the U. S. National Arboretum in 1995 after proving to have a high resistance to Dutch elm disease. 'Valley Forge' proved only moderately successful in the US National Elm Trial, averaging a survival rate of 66.7% overall, owing largely to environmental factors rather than susceptibility to disease.
The American Elm cultivar Ulmus americana 'Washington', of unknown derivation, was sourced from Princeton Nurseries, Princeton, New Jersey, from 1985, and planted on the National Mall, Washington D.C. It was then selected by H. V. Wester of the U. S. National Park Service and introduced for trials as NPS 3-178. Santamour pointed out that as the historic Washington Elm had been propagated as 'Washington', NPS 3-178, if ever registered as a cultivar, would need a different cultivar name.
The American Elm cultivar Ulmus americana 'Patmore' was selected and raised by R. H. Patmore from a native tree in Brandon, Manitoba, Canada. It may be synonymous with another cultivar from the same source, known as 'Brandon'.
The American Elm cultivar Ulmus americana 'Lake City' is a semi-fastigiate form cloned in the early 1920s from a ten-year old seedling found growing outside the Lutheran parsonage, Lake City, Minnesota, and released by the Lake City Nurseries there in 1931. The Nurseries published a nine-page booklet on it in 1932, 'The Lake City Elm', with full description, a photograph of the original tree, and commendatory letters. It was later described by Wyman in Trees Magazine 3 (4): 13, 1940.
The American Elm cultivar Ulmus americana 'Littleford' was cloned from a tree in Hinsdale, Illinois, circa 1915 by Littleford Nurseries of Downers Grove, Illinois, and first released in 1927. It was marketed in the 1930s by nearby Hinsdale Nurseries, successor to Littleford Nurseries, as 'Littlefordii'. In their 1925 catalogue Littleford Nurseries had written of their selection: "The growing of the American elm is a specialty with us; we consider it the leading shade and ornamental tree. Our trees are a selected strain of the V-shaped type, a stock of 15 to 20 thousand, all 2 ins. and up in size, transplanted twice and in splendid vigor for planting".
The American Elm cultivar Ulmus americana 'Moline' was cloned from a wild seedling transplanted to Moline, Illinois, from nearby Rock River Valley in 1903 and propagated from 1916 by the Klehm Nurseries, Arlington Heights, Illinois.
The American elm cultivar Ulmus americana 'Beebe's Weeping' was propagated from a tree growing in the wild at Galena, Illinois, by Mr. E. Beebe in the mid-19th century. Thomas Meehan, who had received cuttings and called it 'Weeping Slippery Elm' before the flowers revealed that it was not Ulmus fulva, suggested the name 'Beebe's Weeping Elm', as there were already U. americana clones called 'Pendula'. In the early 20th century it was marketed, however, as Ulmus 'American Galena Weeping', "American Weeping Elm", by the Klehm nursery of Arlington Heights, Illinois.
The American elm cultivar Ulmus americana 'Ascendens', 'Upright American Elm', was cloned c.1910 by Bernard H. Slavin, Superintendent of Parks, Rochester, New York, from a tree growing in Seneca Park, Rochester, and named in 1927 for its narrow oval form.
The American elm cultivar Ulmus americana 'Aurea' was cloned from a tree discovered by F. L. Temple in Vermont at the end of the 19th century.
The American elm cultivar Ulmus americana 'Beaverlodge' was selected as a seedling in 1925 at the Beaverlodge Experimental Farm, Morden, Manitoba, part of the Lacombe Research Centre, Alberta, for its hardiness and vigour, and released in 1954.
The American Elm cultivar Ulmus americana 'Columnaris' was propagated by R. E. Horsey of the Rochester N.Y. Parks Department from a tree found by Mr John Dunbar at Conesus Lake, New York, in 1911, and originally described as a forma, Ulmus americana L. f. columnaris, f. nov.Rehder (1922). It was the earliest of a number of compact, columnar American elm cultivars, to be followed by 'Ascendens' and 'Augustine Ascendening'.
The American Elm cultivar Ulmus americana 'Fiorei' was raised by the Charles Fiore Nurseries, Prairie View, Illinois, before 1949, and first listed as 'Fiorii', Fiore Elm, without description. It is no longer listed by the company.
The American Elm cultivar Ulmus americana 'Kimley' was cloned c.1957 by the Sheridan Nurseries, Mississauga, Canada, from a large tree found near Oshawa, Ontario, Canada.
The American elm cultivar Ulmus americana 'Burgoyne' stood at the Arnold Arboretum until removed in 1988. Grown for the town of Weston, Massachusetts, the tree was raised in 1965 by Dr. Donald Wyman, retired head horticulturist of Arnold Arboretum, from seeds of the historic Burgoyne Elm, that stood for c.300 years at 626 Boston Post Road, Weston, before being felled in 1967 In October 1777 a contingent of British prisoners-of-war from General Burgoyne's defeated army, captured by General Gates, bivouacked under the original tree, then nearly a century old, on their way to prison in Somerville.
The American Elm cultivar Ulmus americana 'Iowa State' was cloned in the 1980s from a tree discovered by Professor Alexander (Sandy) McNabb of Iowa State University as the sole survivor in 40 acres (16 ha) of diseased elm at Burlington.
The American Elm cultivar Ulmus americana 'L'Assomption' was selected from seedlings grown from X-irradiated seed at the eponymous experimental station in Quebec before 1965.
The American Elm cultivar Ulmus americana 'Jackson' was cloned c.1990 from an elm selected at Wichita, Kansas, which had reputedly shewn no signs of Dutch elm disease damage at over 50 years of age.
The American Elm cultivar Ulmus americana 'Miller Park' is a selection made by the University of Minnesota. Originally identified as MNT-0365, it was cloned from an old elm surviving in Hennepin County, Minnesota. 'Miller Park' is currently (2016) being researched but no data have yet been published. The tree is named for the eponymous park in Eden Prairie, in the environs of Minneapolis.