Ulmus americana 'Lewis & Clark'
Encyclopedia
The American Elm
American Elm
Ulmus americana, generally known as the American Elm or, less commonly, as the White Elm or Water Elm, is a species native to eastern North America, occurring from Nova Scotia west to Alberta and Montana, and south to Florida and central Texas. The American elm is an extremely hardy tree that can...

 Ulmus americana cultivar 'Lewis & Clark' (Prairie Expedition) is a relatively new development from the North Dakota State University
North Dakota State University
North Dakota State University of Agriculture and Applied Sciences, more commonly known as North Dakota State University , is a public university in Fargo, North Dakota. NDSU has about 14,000 students and it is the largest university in North Dakota based on full time students and land size...

 (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 a tree discovered in 1994 along the Wild Rice River
Wild Rice River (North Dakota)
The Wild Rice River is a tributary of the Red River of the North, approximately long, in southeastern North Dakota in the United States. Via the Red River, Lake Winnipeg, and the Nelson River, it is part of the watershed of Hudson Bay. The Wild Rice River drains an area of in the Red River...

 south west of Fargo
Fargo, North Dakota
Fargo is the largest city in the U.S. state of North Dakota and the county seat of Cass County. In 2010, its population was 105,549, and it had an estimated metropolitan population of 208,777...

, ND., where all those around it had succumbed to Dutch elm disease
Dutch elm disease
Dutch elm disease is a disease caused by a member of the sac fungi category, affecting elm trees which is spread by the elm bark beetle. Although believed to be originally native to Asia, the disease has been accidentally introduced into America and Europe, where it has devastated native...

; the tree remains in perfect health (2008).

Description

'Lewis & Clark' is distinguished in maturity by its broad umbrella crown and dark green foliage. http://www.qscaping.com/NetPS-Engine.asp?CCID=20000011&page=pdp&PID=4180 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 < 13 cm in length by 9 cm broad, coarsely-toothed, and with a 4 mm petiole
Petiole (botany)
In botany, the petiole is the stalk attaching the leaf blade to the stem. The petiole usually has the same internal structure as the stem. Outgrowths appearing on each side of the petiole are called stipules. Leaves lacking a petiole are called sessile, or clasping when they partly surround the...

.

Pests and diseases

Possession of an innate resistance to Dutch elm disease was suggested after inoculation with the causal fungus at the NDSU , however replication of the tests is considered too limited to be conclusive. No other specific information available, but the species generally is highly susceptible to Elm Yellows
Elm Yellows
Elm Yellows is a plant disease of elm trees that is spread by leafhoppers or by root grafts. Elm Yellows, also known as Elm Phloem Necrosis, is very aggressive, with no known cure. Elm Yellows occurs in the Eastern United States and southern Ontario in Canada. It is caused by phytoplasmas which...

; it is also moderately preferred for feeding and reproduction by the adult Elm Leaf Beetle Xanthogaleruca luteola
Xanthogaleruca luteola
Xanthogaleruca luteola, commonly known as the Elm Leaf Beetle, is a serious pest of the elm. Indigenous to Europe, it was accidentally introduced to North America. Both the imagines and larvae feed on the emergent leaves of the elm...

http://www.bioone.org/doi/full/10.1603/0022-0493%282001%29094%5B0162%3AROTCEU%5D2.0.CO%3B2, and highly preferred for feeding by the Japanese Beetle Popillia japonica http://www.bioone.org/doi/full/10.1603/0022-0493%282001%29094%5B0445%3APOTCEU%5D2.0.CO%3B2 http://www.sunshinenursery.com/survey.htm in the USA.
U. americana is also the most susceptible of all the elms to verticillium wilt
Verticillium wilt
Verticillium Wilt is a wilt disease of over 300 species of eudicot plants caused by one of two species of Verticillium fungus, V. dahliae and V. albo-atrum. Many economically important plants are susceptible including cotton, tomatoes, potatoes, eggplants, peppers and ornamentals, as well as others...

 .

Cultivation

'Lewis & Clark' (Prairie Expedition) has been included in the National Elm Trial
National Elm Trial
The National Elm Trial is an American volunteer effort to evaluate a range of newly developed elm cultivars as replacements for elms destroyed by Dutch elm disease...

 coordinated by Colorado State University
Colorado State University
Colorado State University is a public research university located in Fort Collins, Colorado. The university is the state's land grant university, and the flagship university of the Colorado State University System.The enrollment is approximately 29,932 students, including resident and...

. The tree is in commerce in the USA, and was introduced to the UK in 2008, but is not known to have reached continental Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

 or Australasia
Australasia
Australasia is a region of Oceania comprising Australia, New Zealand, the island of New Guinea, and neighbouring islands in the Pacific Ocean. The term was coined by Charles de Brosses in Histoire des navigations aux terres australes...

.

Europe

  • Great Fontley Farm, Fareham
    Fareham
    The market town of Fareham lies in the south east of Hampshire, England, between the cities of Southampton and Portsmouth, roughly in the centre of the South Hampshire conurbation.It gives its name to the borough comprising the town and the surrounding area...

    , UK, Butterfly Conservation
    Butterfly Conservation
    Butterfly Conservation is an insect conservation organisation in the United Kingdom. It is one of the largest insect conservation organisations in the world.-History of the Organisation:...

    Elm trials plantation, Home Field, E1, H1. Two 1.2 m trees planted 2008.

North America


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
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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