Ulmus × intermedia 'Willis'

The hybrid elm cultivar Ulmus × intermedia 'Willis' originated as a crossing made by a Mr Minnick of Kansas. Almost certainly derived from a crossing of the Siberian Elm Ulmus pumila (female parent) and the Red Elm Ulmus rubra, it was originally believed that the male parent was the American Elm Ulmus americana.[1]

Ulmus × intermedia cultivar
Hybrid parentageU. pumila × U. rubra
Cultivar'Willis'
OriginUS

Description

'Willis' was described as having a smooth grey bark, large leaves similar to U. americana, and capable of very rapid growth.[1]

Pests and diseases

In 1995 Santamour reported the cultivar "not widely tested for resistance to Dutch elm disease".[2] Elowsky, Jordon-Thaden, and Kaul (2013) refer to more recent papers on the subject.[3]

Cultivation

First marketed by the Willis Nursery Co., Ottawa, Kansas, circa 1959,[2] it is not known whether the cultivar remains in cultivation in the United States, nor whether it was ever introduced to Europe or Australasia.

References

  1. Green, Peter Shaw (1964). "Registration of cultivar names in Ulmus". Arnoldia. Arnold Arboretum, Harvard University. 24 (6–8): 41–80. Retrieved 16 February 2017.
  2. 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.
  3. Elowsky, C.G.; Jordon-Thaden, I.E.; Kaul, R.B. (10 July 2013). "A morphological analysis of a hybrid swarm of native Ulmus rubra Muhl. and introduced U. pumila L. (Ulmaceae) in southeastern Nebraska" (PDF). Phytoneuron. 2013–44: 1–23. ISSN 2153-733X. Archived from the original (PDF) on 5 October 2022. Retrieved 25 October 2017.
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