Rock elm (Ulmus thomasii)

Rock elm leaves

Click on the images help you identify an Rock elm.



Height 60' to 70', diameter 24" to 48"; straight trunk; somewhat conical head with long, graceful branches.


Ash gray; divided by deep fissures into broad, flat ridges; outer bark layers alternating white and brown in cross section.


Simple, alternate on stem, length 2" to 4"; deep green, doubly toothed margins, uneven base; turns yellow in autumn.

Fruit (seed)

Winged samara, 1/2" long; ovate, wafer like, contains one seed, slightly notched at outer end; ripens in early summer.


Commonly found on bottomlands in the eastern and south-central parts of the state, especially in the Minnesota River Valley, and continues as far northward as Clearwater County. Moderately shade tolerant, fast growing.

Wood uses

Extremely hard and tough, difficult to split, only moderately resistant to decay; sapwood is nearly white in mature trees; used for parts of heavy agricultural implements, vehicles, handles, and boats.

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