The American Elm
cultivar
A cultivar is a kind of Horticulture, cultivated plant that people have selected for desired phenotypic trait, traits and which retains those traits when Plant propagation, propagated. Methods used to propagate cultivars include division, root a ...
''Ulmus americana'' 'Iowa State' was cloned in the 1980s from a tree discovered by Professor Alexander (Sandy) McNabb of
Iowa State University
Iowa State University of Science and Technology (Iowa State University, Iowa State, or ISU) is a Public university, public land-grant university, land-grant research university in Ames, Iowa, United States. Founded in 1858 as the Iowa Agricult ...
as the sole survivor in of diseased elm at
Burlington.
Description
The tree is possessed of a fastigiate, thickly-branched habit, but has relatively weak branch unions owing to acute angles of attachment leading to bark inclusions.
Pests and diseases
'Iowa State' was reported in the ''American Horticulturist'' News Edition, 63(5):4, 1984, as "a natural selection from southeastern Iowa, highly resistant to
Dutch elm disease when inoculated". 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
''Xanthogaleruca luteola'', commonly known as the elm-leaf beetle, is a beetle species in the family Chrysomelidae that is native to Europe but invasive in other parts of the world.http://cisr.ucr.edu/elm_leaf_beetle.html - Center for Invasive ...
'',
and highly preferred for feeding by the Japanese Beetle ''
Popillia japonica
The Japanese beetle (''Popillia japonica'') is a species of scarab beetle. Due to the presence of natural predators, the Japanese beetle is not considered a pest in its native Japan, but in North America and some regions of Europe, it is a no ...
''
in the United States. ''U. americana'' is also the most susceptible of all the elms to
verticillium wilt
Verticillium wilt is a wilt disease affecting over 350 species of eudicot plants. It is caused by six species of '' Verticillium'' fungi: ''V. dahliae'', ''V. albo-atrum'', ''V. longisporum'', ''V. nubilum'', ''V. theobr ...
.
[Pegg, G. F. & Brady, B. L. (2002). ''Verticillium Wilts''. CABI Publishing. ]
Cultivation
The cultivar was trialed in Minneapolis.
[ One of the original plantings (1978) in the Dean Park area of Minneapolis had to be felled in 2012, 34 years later, after serious defects developed.][Blair, (2013). Goodbye to 'Iowa State'. ''Elm Archives - Trees''. University of Minnesota]
/ref>
References
{{Elm species, varieties, hybrids, hybrid cultivars and species cultivars , state=collapsed
American elm cultivar
Ulmus
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