Ulmus americana 'St. Croix'

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Ulmus americana 'St Croix'
Species Ulmus americana
Cultivar 'St. Croix'
Origin St. Paul, Minnesota, US

The American Elm cultivar Ulmus americana 'St. Croix' is a recent (2008) selection cloned from a large tree growing on a farm near Afton, Minnesota, [1] which has displayed a high resistance to Dutch elm disease (DED). [2] A U S patent, PP 20097, was granted in 2009.

Contents

Description

‘St. Croix’ has an open-grown, spreading, vase-shaped crown. The growth rate is fast and typical of the species in Minnesota. The bark is typically divided into grayish, flat-topped ridges, which are separated by roughly diamond-shaped fissures and which become indefinite in pattern in the canopy. Bark on young branches is smooth with inconspicuous lenticels. The twigs are slender, zigzag, brown, glabrous or slightly pubescent; lateral buds are about 6 mm long, ovoid, acute but not sharp-pointed, smooth or sparingly downy, chestnut-brown. Leaves are deciduous, simple, alternate, short-petioled, 2-ranked, dark green (closest to 006600 on HTML True Color Chart), 10–15 cm (4–6 inches) long, 2.5–5 cm (1–2 inches) wide and oblong-obovate to elliptical, the margin coarsely doubly serrate, the apex acuminate while the base is typically inequilateral; surfaces glabrous (smooth) or slightly scabrous (roughened) above, usually pubescent below; veins alternate, ascending, parallel and extending from central vein to apex of longest serrations. The perfect apetalous wind-pollinated flowers are vernal, appearing before the leaves unfold, born in long-pedicelled fascicles of 3 or 4. The fruit is a samara maturing in the spring as the leaves unfold; about 12 mm (½ inch) long, oval to oblong-obovate, deeply notched at apex, margin ciliate with smooth surfaces. [3]

The parent tree at Afton had a d.b.h. of 1.9 m when measured in 2008.

Pests and diseases

Resistance to Dutch elm disease has been confirmed by inoculation trials conducted at Minnesota State University. Tested alongside established cultivars 'Valley Forge', 'Miller Park', and wild specimens, all three cultivars became symptomatic but survived, whereas the wild trees died. [3] However, the relative percentages of defoliation and dieback of the three cultivars have not been disclosed. The species as a whole is susceptible to Elm Yellows; it is also moderately preferred for feeding and reproduction by the adult Elm Leaf Beetle Xanthogaleruca luteola , [4] and highly preferred for feeding by the Japanese Beetle Popillia japonica [5] [6] in the United States. U. americana is also the most susceptible of all the elms to verticillium wilt. [7]

Cultivation

The tree is propagated and marketed by Bailey Nurseries , of Newport, Minnesota.

Etymology

The tree is named for the St. Croix river valley.

Accessions

North America

Related Research Articles

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 'Exhibition' is a selection made by the Patmore Nurseries from seeds of a tree at Brandon, Manitoba. Released in 1952, 'Exhibition' was propagated by grafting.

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 '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.

<i>Ulmus americana</i> Aurea Elm cultivar

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.

<i>Ulmus americana</i> Beaverlodge Elm cultivar

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.

<i>Ulmus americana</i> Columnaris Elm cultivar

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 'Morden' was cloned from a selection made by the Dominion Experimental Farm, Morden, Manitoba, in 1939 on account of its ability to withstand severe ice storms without breakage.

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 'Flick's Spreader' was cloned from a tree discovered by John T. Flick on a farm near Hammon, Oklahoma. Cuttings were given to the Sunshine Nursery, Clinton, Oklahoma, in 1997, which later marketed the tree as 'Flick's Spreader'.

The American Elm cultivar Ulmus americana 'Creole Queen' was cloned from a tree growing outside New Orleans and was released in 2008.

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.

References

  1. ↑ 'The St. Croix Elm: How a chance encounter in Afton may resurrect an American icon'; Minneapolis & St Paul Magazine, 1 February 2014; mspmag.com/arts-and-culture
  2. ↑ Palmer, K. Star Tribune, May 5, 2009.
  3. 1 2 Bliska, C., Bliska, P., Stennes, M., & Giblin, C. (2008). American elm tree named 'St. Croix', Patent Application US 20080196132 P1
  4. ↑ Miller, Fredric; Ware, George (2001-02-01). "Resistance of Temperate Chinese Elms (Ulmus spp.) to Feeding by the Adult Elm Leaf Beetle (Coleoptera: Chrysomelidae)". Journal of Economic Entomology. 94 (1). Oxford University Press (OUP): 162–166. doi: 10.1603/0022-0493-94.1.162 . ISSN   0022-0493. PMID   11233108.
  5. ↑ Miller, Fredric; Ware, George; Jackson, Jennifer (2001-04-01). "Preference of Temperate Chinese Elms ( Ulmus spp.) for the Adult Japanese Beetle (Coleoptera: Scarabaeidae)". Journal of Economic Entomology. 94 (2). Oxford University Press (OUP): 445–448. doi: 10.1603/0022-0493-94.2.445 . ISSN   0022-0493. PMID   11332837.
  6. ↑ "Elm Leaf Beetle Survey". Archived from the original on 2011-07-19. Retrieved 17 July 2017.
  7. ↑ Pegg, G. F.; Brady, B. L., eds. (2002). Verticillium wilts. Wallingford: CABI. doi:10.1079/9780851995298.0000. ISBN   978-0-85199-529-8.
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