Ulmus 'Hamburg'

The hybrid elm cultivar Ulmus 'Hamburg' was originally raised by the Plumfield Nurseries, Fremont, Nebraska, circa 1932, after its discovery by Mr. Lloyd Moffet in a bed of Siberian Elm Ulmus pumila seedlings from Tekamah.[1] It was later marketed by Interstate Nurseries, Hamburg, Iowa, from 1948, as 'Interstate's New Hamburg Hybrid Elm'. Green stated that it was originally said be a hybrid of Ulmus pumila (female parent) and Ulmus americana,[2] but the Hamburg Nurseries of Iowa made no such claim for it in their catalogues from 1948 onwards.[3][4][5] It is now considered more likely that Ulmus rubra was the male parent, as it was also known as 'Hybrid Chinese Elm',[2] and therefore probably synonymous with Plumfield Nurseries' 'Hybrid elm' of the same date, a known crossing of U. pumila and U. rubra,[6][7] – and so, perhaps, also synonymous with Ulmus × intermedia 'Fremont', an elm of the same parentage found a little later in Plumfield Nurseries.

Ulmus 'Hamburg'
GenusUlmus
Cultivar'Hamburg'
OriginUS

An U. pumila × U. rubra parentage would, by present classification, make the cultivar Ulmus × intermedia 'Hamburg' .

A similar erroneously conjectured crossing with U. americana occurred at Plumfield Nurseries in the 1930s, with their so-called "Wheatley hybrid elm" (apparently not the European 'Wheatley'), briefly marketed in 1934: "Our variety, an attractive round-headed rapid growing tree, with medium sized glossy leaves; originally imported from Holland and hybridized with American white elm, Ulmus americana ".[8]

Description

'Hamburg' has been described as a hardy, very rapid grower, with much stronger branching than the Siberian Elm.[9][10] Hamburg Nurseries described it as "a shapely tree with large, dark green leaves".[5] Leaves 3 to 4.5 inches long, 1.5 to 2 inches wide.[11]

Pests and diseases

'Hamburg' had not (by 1995) been widely tested for resistance to Dutch elm disease.[9]

Cultivation

Largely confined to the United States, several were introduced to the UK. A tree in Exeter University Botanic Gardens, Exeter, Devon, however, at one time listed as 'Hamburg Hybrid' (TROBI Champion, 17 m high, 55 cm d.b.h.), has since been found to be Ulmus laevis. 'Hamburg' is not known to have been introduced to Australasia.

Notable trees

Two well-grown specimens, planted in 1953 and therefore among the earliest specimens sourced from the Hamburg Nurseries, stand (2022) in Arnold Arboretum, Massachusetts, USA.[11]

Synonymy
  • 'Hamburg Hybrid Elm': Interstate Nurseries, Hamburg, Iowa, Catalogue, Spring 1949.
  • 'Hybrid Chinese Elm': Plumfield Nurseries, Fremont, Nebraska.[7]

Accessions
North America

References
  1. 'Interstate's New Hamburg Hybrid Elm'; Inter-State Nurseries, Hamburg, Iowa : spring 1950 catalogue; p.34
  2. Green, Peter Shaw (1964). "Registration of cultivar names in Ulmus". Arnoldia. Arnold Arboretum, Harvard University. 24 (6–8): 41–80. Retrieved 16 February 2017.
  3. 'Interstate's New Hamburg Hybrid Elm'; Inter-State Nurseries spring 1948 catalogue; p.34
  4. 1949 Photograph of young 'Hamburg': 'Interstate's New Hamburg Hybrid Elm'; Inter-State Nurseries, Hamburg, Iowa : spring 1949 catalogue; p.34
  5. Inter-State Nurseries, Hamburg, Iowa : spring 1950 catalogue; p.34
  6. Plumfield Nurseries, Fremont, Nebraska, 1942 catalogue, p.20
  7. Plumfield Nurseries, Fremont, Nebraska, 1943 catalogue, p.22
  8. L.A. Moffet, manager, Plumfield Nurseries, Fremont, Nebraska: Wholesale trade list for nurserymen, florists and dealers: February 10, 1934; p12
  9. 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.
  10. Ulmus 'Hamburg' in Handbuch der Ulmengewächse, www.ulmen-handbuch.de
  11. U. rubra x U. pumila ('Hamburg'); ulmen-handbuch.de
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