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.
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] '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".