Fraxinus anomala

Single Leaf Ash

Image 1. Fraxinus anomala

Figure 2. Single, ovate shaped leaves present on Fraxinus anomala; photo by Trent M. Draper.

Figure 3. Location of Fraxinus anomala in the state of Utah

Fraxinus anomala (Image 1) literally means anomalous ash. As its name states it is an anomaly, because it is the only ash species with simple, single leaves (Image 2) instead of compound leaves. This shrub/tree is distinguished by its dark bark, stubby twigs, and dense, vertical growth pattern. It is known more commonly as the single leaf ash. Single leaf ash was discovered independently in the late 1850’s by Newberry and Palmer. This shrub/tree remained nameless until 1871, when it was named by John Torrey.

Description

Fraxinus anomala is a species of ash with single, ovate shaped leaves. These leaves are smooth, glossy, and slightly toothed on the leaf margin. They are a green color and are 1.5-6.5 centimeters in length and 1-6 centimeters in width. Single leaf ash is a perennial with growth periods during the spring and summer. It exhibits moderate growth rates and grows to an approximate height of 2.5-4 meters. The form of its growth is multiple stem and erect. It flowers in mid-spring and its seeds are dispersed during the spring by wind since they are winged. The flowers are yellow and the seeds are brown.

Habitat

Fraxinus anomala is a native species to the United States of America. It is typically located in draws and/or canyons where water collects due to events due to run off or storms. Single leaf ash commonly occurs at elevations between 1200-1800 meters. It is very common in Utah (Image 3) and northern Arizona, but it can also be found in Colorado and extreme northwest New Mexico.

Growth Requirements

Fraxinus anomala not only has the ability to grow at these relatively high elevations but it also possesses another very important quality. It is very well adapted to xeric landscapes that are present in the locations listed above. This is due to its tolerance to drought, heat, and high soil pH. Also it is adapted to course and medium textured soils. It is intolerant to shade and can survive to a minimum temperature of 5° C.

David Jones, Fall 2007