The elm cultivar Ulmus 'Monstrosa' is believed to have originated in France, where it was listed without description as a form of Field Elm, Ulmus campestris var. monstrosa. Krüssman included it in his manual as an Ulmus glabra cultivar, but the plant's long, slender 2 cm petiole, if correctly reported, is not a feature of U. glabra, and is even less likely in a shrub form of this tree.
'Monstrosa' is a compact shrub, with branchlets often fasciated, and leaves 5–8 cm long, partly pitcher-shaped at the base, and on slender stalks < 25 mm long.
No authoritatively identified specimens are known to survive. A 'Monstrosa' at the Ryston Hall , Norfolk, arboretum, obtained from the Späth nursery in Berlin before 1914, was killed by the earlier strain of Dutch elm disease prevalent in the 1930s. The shrub elm sold in the Netherlands as 'Monstrosa' appears from photographs to be the cultivar 'Nana'.
- Ulmus campestris (: glabra) var. monstrosa: Lavallée, Arboretum Segrezianum 235, 1877, and Hartwig, Illustrirtes Gehölzbuch ed. 2, 294, 1892.
- Ulmus scabra (: glabra) var. monstrosa Hort.; Krüssmann, Handbuch der Laubgehölze 2: 536, 1962, as a cultivar.
- Green, Peter Shaw (1964). "Registration of cultivar names in Ulmus". Arnoldia. Arnold Arboretum, Harvard University. 24 (6–8): 41–80. Retrieved 16 February 2017.
- Johann Gerd Krüssmann, Handbuch der Laubgehölze 2: 536, 1962
- Ryston Hall Arboretum catalogue. c. 1920. pp. 13–14.
- Photographs of plant sold as 'Monstrosa' in Holland: Herman Geers Dwarf & Miniature Plants,