Ulmus americana 'Lewis & Clark'

Infobox Cultivar | name = "Ulmus americana"


image_caption = 'Lewis & Clark' leaves, midsummer
cultivar = 'Lewis & Clark' Prairie Expedition™
origin = North Dakota State University Research Foundation, USAThe American Elm "Ulmus americana" cultivar 'Lewis & Clark' (Prairie Expedition™) is a new development from the North Dakota State University (NDSU) Research Foundation breeding programme, released in 2004 to commemorate the 200th anniversary of the eponymous expedition [http://ndsuresearchfoundation.org/PrairieExpedition-RFM-37.htm] . The cultivar was cloned from one remarkable tree discovered in 1994 along the Wild Rice River south west of Fargo, ND., which had apparently survived Dutch elm disease; the tree remains in perfect health (2008).

Description

'Lewis & Clark' is distinguished by its broad umbrella crown and dark green foliage. The clone grows very rapidly, averaging an increase of > 1 m in height per annum when young, and reaching a height of up to 17 m. in 25 to 30 years [http://ndsuresearchfoundation.org/horticulture.htm] . The leaves are < 130 mm in length by 90 mm broad, coarsely-toothed, and with a 4 mm petiole.

Pests and diseases

Possession of an innate disease-resistance was suggested after inoculation with the causal fungus at the NDSU Capps, T. K. (1996). "Selection, propagation and inoculation of American Elms with potential Dutch elm disease resistance". MSc thesis, NDSU.] , however replication of the tests is considered too limited to be conclusive.

Cultivation

'Lewis & Clark' (Prairie Expedition™) has been included in the National Elm Trial coordinated by Colorado State University. The tree is available from a small number of nurseries in North America, and was introduced to the UK in 2008, but is not known to have reached continental Europe or Australasia.

Etymology

The tree is named for the Lewis & Clark prairie expedition of 1804.

Accessions

North America

*North Dakota State University, no details known.

Europe

*Great Fontley Farm, Fareham, UK, "Butterfly Conservation" Elm trials plantation, Home Field. Two 1.2 m trees planted 2008.

Nurseries

*Lee Nursery Inc. [http://www.leenursery.com/isite/subcat.cfm?CatID=270&CatName=Deciduous%20Trees&start=true] , Fertile, Minnesota.
*Jeffries Nurseries Ltd [http://www.jeffriesnurseries.com/catalogue.htm] , Portage la Prairie, Manitoba, Canada.
*Bylands Nurseries Ltd. [http://www.bylands.com/Home/tabid/543/Default.aspx] , Kelowna, British Columbia, Canada.

References

External links

*http://ndsuresearchfoundation.org/Prairie%20Expedition-RFM-37.htm "U. americana" Lewis & Clark Prairie Expedition NDSU Plant Sciences Introduction.
*http://treehealth.agsci.colostate.edu/research/nationalelmtrial/NationalElmTrial.htm National Elm Trial