Single Leaf Ash is, as its specific epithet indicates, an anomaly.  It is the only Ash which almost always has single, not compound, leaves, i.e., its leaves are almost always whole, not cut into leaflet divisions.  Very seldomly one may find Fraxinus anomala with compound leaves with three divisions, and rarely one may find five divisions.  (Click to see various leaf shapes).

Fraxinus anomala has multiple trunks, is typically 8-14 feet tall, and is found near washes and in rocky areas.

In both photograph at left, the trees pictured have young spring leaves that will grow and fill in the airy spaces.  Because the tree in the top photograph is growing in a canyon bottom near a small stream, it is less branched than most Single Leaf Ash trees and does not have as many dead branches as other Single Leaf Ash.  This tree is about twelve feet tall with the largest of its multiple trunks over three inches in diameter.

The second photograph shows how glistening green Fraxinus anomala leaves are and thus how easy it is to spot the tree even from a distance.  

Linnaeus named this genus in 1753: "Fraxinus" is the ancient Latin name given to Ash trees.   Fraxinus anomala was collected by Newberry and Palmer independently in Utah in the late 1850s and was named by John Torrey in 1871.

Semi-desert, foothills. Woodlands, openings, rocks, canyons. Spring.
Near McElmo Canyon, May 14, 2004,
Hunter Canyon, Utah, May 3, 2005.

Handsome leaves may be almost smooth-margined, slightly serrated, or (as in the third photograph), sharply serrated. 

Massive cluster of tiny, petal-less, and short-lived flowers change from yellow to light greenish-yellow.

Although  Fraxinus anomala most often grows with a vertical posture, it is quite common to find it sprawling in an intricate shrub pattern.

Fall colors are golden yellows.

Range map © John Kartesz,
Floristic Synthesis of North America

State Color Key

Species present in state and native
Species present in state and exotic
Species not present in state

County Color Key

Species present and not rare
Species present and rare
Species extirpated (historic)
Species extinct
Species noxious
Species exotic and present
Native species, but adventive in state
Eradicated
Questionable presence

Range map for Fraxinus anomala