Cedar Elm

''Ulmus crassifolia'' Nutt., the Texas cedar elm or simply cedar elm, is a deciduous tree native to south-central North America, mainly in southern and eastern Texas, southern Oklahoma, Arkansas, and Louisiana, with small populations in western Mississippi, southwest Tennessee, and north-central Florida; it also occurs in northeastern Mexico.Todzia, C. A. & Panero, J. L. (2006). A new species of Ulmus (Ulmaceae) from southern Mexico and a synopsis of the species in Mexico. ''Brittonia'', Vol 50, (3): 346 It is the most common elm tree in Texas. The tree typically grows well in flat valley bottom areas referred to as cedar elm flats. Its Latin name refers to its comparatively thick (crassifoliate) leaves; the common name cedar elm is derived from the trees' association with juniper trees, locally known as cedars.

Description

The cedar elm is a medium to large deciduous tree growing to 24–27 m tall with a rounded crown. The leaves are small, 2.5–5 cm long by 1.3–2 cm broad, with an oblique base, and distinguish it from ''Ulmus serotina'' with which it readily hybridizes in the wild. Leaf fall is late, often in early winter. The wind-pollinated apetalous perfect flowers are produced in the late summer or early fall; they are small and inconspicuous, with a reddish-purple color, and hang on slender stalks a third to a half inch long. The fruit is a small winged samara 8–10 mm long, downy on both surfaces at first, maturing quickly after the flowering in late fall.Elwes, H. J. & Henry, A. (1913). ''The Trees of Great Britain & Ireland'', Vol. VII, p.1929. Republished 2004 Cambridge University Press


Image:Ulmus crassifolia (USDA).jpg, ''U. crassifolia'' bark
File:Ulmus_crassifolia_kz02.jpg, ''U. crassifolia'' foliage, Botanischer Garten, Berlin-Dahlem
File:Winged Elm Ulmus alata 2009-05-10.jpg, ''U. crassifolia'' branchlet, Spring Creek, Garland, Texas
Ulmus crassifolia leaves.jpeg, ''U. crassifolia'' leaves and fruit, November
File:MonarchButterfly-5635.jpg, Migrating monarch butterflies on a cedar elm in central Texas

Pests and diseases

Cedar elm is susceptible to Dutch elm disease (DED), though less so than American elm, and moderately damaged by the elm leaf beetle ''Xanthogaleruca luteola''. The tree also suffers from a vascular wilt, the symptoms often confused with those of DED.

Cedar elms are very susceptible to mistletoe. Mistletoe is a parasite that roots itself into the vascular system of the tree, thus stealing valuable nutrients and water. In some cases, if not removed, the parasite can be devastating to large sections of trees and even fatal. They create club-like branches that die out at the ends. These "club" branches create openings for future pests such as the elm beetles and carpenter ants. No treatments are known to be safe enough to kill mistletoe without killing the tree. Removing the mistletoe manually is not a guarantee, but it is the best-known method for control.

Cedar elms are known to be highly immune to Texas root rot caused by the fungus ''Phymatotrichopsis omnivora''. Because of this, it is usually planted in regions where ''P. omnivora'' is prevalent, since the closely related lacebark elm is highly susceptible and easily killed by the fungus.

Cultivation

''U. crassifolia'' is extremely rare in cultivation in Europe and Australasia. Specimens were supplied by the Späth nursery of Berlin from the late 19th century. Henry (1913) and Bean (1988) note that it does not thrive in northern Europe, where the branchlets often die back. Three trees supplied by Späth to the Royal Botanic Garden Edinburgh in 1902 as ''U. crassifolia'' may survive in Edinburgh, as it was the practice of the garden to distribute trees about the city (viz. the Wentworth elm).

Notable trees

The US national champion, measuring 37 m high in 2001, grows in the Meeman-Shelby Forest State Park, Tennessee.American Forests. (2012). The 2012 National Register of Big Trees.

Cultivars

* Brazos Rim (elm cultivar), 'Brazos Rim'.

Hybrids

* '' Ulmus × arkansana'' ''U. crassifolia'' × ''U. serotina'' Present in Arkansas and Oklahoma.

Accessions

North America

* Arnold Arboretum, US. Acc. nos. 511–2002, 758–86, both wild collected
* Chicago Botanic Garden, US. No details available.
* Bartlett Tree Experts, US. Acc. no. 90–1243, unrecorded provenance.
* Morton Arboretum, US. Acc. no. 385–68, 14-86
* New York Botanical Garden, US. Acc. no. 79617, unrecorded provenance.
* U S National Arboretum, Washington, D.C., US. Acc. no. 37834

Europe

* Grange Farm Arboretum, Lincolnshire, UK. Acc. no. 509
* Royal Botanic Garden Edinburgh, UK. Acc. no. 20080090, from seed wild collected in US.
* Sir Harold Hillier Gardens, UK. Acc. no. 1980–0443, (Brentry Field).
* University of Copenhagen Botanic Garden, Denmark. No details available.

Australasia

* Manukau Cemetery & Crematorium, Auckland, New Zealand. No details available.

Nurseries

North America

Widely available

Europe

* Arboretum Waasland, Nieuwkerken-Waas, Belgium.

Australasia

None known.

References

External links

''Ulmus crassifolia'', Image Archive of Central Texas Plants, University of Texas at Austin, sbs.utexas.edu''U. crassifolia'', Flora of North America, www.efloras.org

{{Taxonbar, from=Q7879431

crassifolia
Trees of Northern America
Plants used in bonsai
Ulmus articles with images
Elm species and varieties
Ulmus Edinburgh Spath 1902