Ulmus thomasii
Habit | tree
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Height: | ⇕ | 100 ft"ft" can not be assigned to a declared number type with value 100. |
Width: | ⇔ | 40 ft"ft" can not be assigned to a declared number type with value 40. |
Lifespan: | ⌛ | perennial |
Exposure: | ☼ | sun |
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USDA Zones: | 2 to 9 |
Ulmaceae > |
Ulmus > |
thomasii > |
Ulmus thomasii Sarg., the Rock Elm or Cork Elm, is a deciduous tree native primarily to the Midwestern United States. The tree ranges from southern Ontario and Quebec, south to Tennessee, west to northeastern Kansas, and north to Minnesota.[1] Its preferred habitat is moist but well-drained sandy loam, loam, or silt loam soil, mixed with other hardwoods; it is moderately shade-tolerant [1]. However, it also grows on dry uplands, especially on rocky ridges and limestone bluffs.
The tree grows from 15-30 m tall and may live up to 300 years. Where forest-grown, the crown is cylindrical and upright with short branches, and is narrower than most other elms. Rock Elm is also unusual among elms in that it usually has a monopodial growth habit. [2]. The bark is grey-brown and deeply furrowed into scaly, flattened ridges. Many older branches have 3-4 irregular thick corky wings. It is for this reason the Rock Elm is sometimes called the Cork Elm.
The leaves are 5 - 10 cm long and 2 - 5 cm wide, oval to obovate with a round, symmetrical base and acuminate apex. The leaf surface is shiny dark green, turning bright yellow in autumn; the underside is pubescent. The perfect apetalous, wind pollinated flowers are red-green and appear in racemes < 40 mm long two weeks before the leaves from March to May, depending on the tree's location. The fruit is a broad ovate samara 13 - 25 mm long covered with fine hair, notched at the tip, and maturing during May or June to form drooping clusters at the leaf bases. [3].
Read about Ulmus thomasii in the Standard Cyclopedia of Horticulture
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Ulmus racemosa, Thomas, not Borkh. (U. Thomasii, Sarg.). Cork Elm. Rock Elm. Tree, attaining 100 ft., with short spreading branches, forming an oblong round-topped head: branchlets pubescent usually until the second year and mostly irregularly corky winged when older: buds acute, pubescent: lvs. oval to oblong-obovate, unequal at the base, shortly acuminate, sharply and doubly serrate, glabrous or somewhat rough above, pubescent beneath, 2-4 in. long: fls. in slender pendulous racemes; calyx with 5-8 exserted stamens: fr. oval or obovate, with a shallow notch at the apex, pale, pubescent, 1/2 – 3/4 in. long. Que. to Tenn., west to Neb.
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Cultivation
Propagation
Pests and diseases
Like most North American elms, the Rock Elm is very susceptible to Dutch elm disease.
Varieties
Gallery
References
- ↑ http://esp.cr.usgs.gov/data/atlas/little/ulmuthom.pdf
- ↑ Bean, W. J. (1981). Trees and shrubs hardy in Great Britain, 7th edition. Murray, London.
- ↑ White, J & More, D. (2003). Trees of Britain & Northern Europe. Cassell's, London.
External links
- w:Ulmus thomasii. Some of the material on this page may be from Wikipedia, under the Creative Commons license.
- Ulmus thomasii QR Code (Size 50, 100, 200, 500)