The Genus Fraxinus
Ash
Family: Oleaceae
The most famous ash in our region is most likely the velvet ash (Fraxinus velutina) which is always a tree. But several species of ash are shrubby plants. There are 63 species of Fraxinus widespread throughout much of Europe, Asia, and North America. Most are deciduous trees and shrubs but a few are evergreen.
The common English name for the genus, "ash", traces back to the Old English æsc, which relates to the Proto-Indo-European for the tree, while the generic name originated in Latin from a Proto-Indo-European word for birch. Both words are also used to mean "spear" in their respective languages, as the wood is good for shafts.
Photo of Gregg’s Ash (Fraxinus greggii) by Mountain States Wholesale Nursery.
Our native ash species are larval host for many moths and butterflies including the Calleta silkmoth (Eupackardia calleta), the great ash sphinx moth (Sphinx chersis), the Sonoran sphinx moth (Ceratomia sonorensis), many Geometrid moths (family Geometridae), and the two-tailed swallowtail (Papilio multicaudata). Ash trees produce single-seeded samaras (winged pod) that granivorous animals use for food.
Ash is a hardwood and is dense and very strong but elastic; extensively used for making bows, tool handles, baseball bats, and other uses demanding high strength and resilience. It lights and burns easily, so is used for starting fires and barbecues, and is usable for maintaining a fire, though it produces only a moderate heat.
Single-Leaf Ash
Fraxinus anamola
Deciduous shrub (rarely a tree) growing 6-20’ high and wide. In spring, along with the emergence of the leaves, yellow flowers appear which are followed by samaras. This species is unusual in the genus in that some (though not all) specimens have simple leaves instead of the pinnate leaves more characteristic of the group (this lends its specific epitaph, anomala).
Grow in full to part sun, with moderate water, hardy to −25 °F.
Found in canyons and bottomlands in lower elevations, often on dry slopes in higher elevations, ranges from 2,000-8,000 ft. in Arizona, Utah, Colorado, Nevada, California and New Mexico.
Photo by Becky Escalante, iNaturalist
Fraxinus anomala on SEINET
Fragrant Ash
Fraxinus cuspidata
Deciduous shrub or small tree, growing to 10-20’ high and wide. Definitely the most showy blooms of the genus. Flowers opening in spring as leaves unfurl; white and fragrant with large petals. Flowers are followed by a samara.
Grow in full to part sun, with moderate water, hardy to about 5°F.
The blooms are fragrant like jasmine.
Native to hillsides, slopes, and canyons in northern Mexico and the southwestern United States—Nuevo León, Coahuila, Chihuahua, Tamaulipas, Texas, New Mexico, Arizona and Nevada.
Goodding’s Ash
Fraxinus gooddingii
Large shrub or small tree, 10-20’ tall. This species is dioecious (separate sexes on separate plants); small and inconspicuous, males purple to yellow-green, females yellow-green, both are borne in small clusters in spring. Flowers are followed by a samara. In the low desert plants are mostly evergreen, semi-evergreen to deciduous in colder regions.
Grow in full to part sun, moderate water, hardy to 10°F
Dry, rocky slopes and ridges of canyons; in desert, grassland, and oak woodland in Arizona and into the northern end of the Sierra Madre Occidental, in Sonora and Chihuahua.
Photo by Eric Hough, iNaturalist
Fraxinus gooddingii on SEINET
Gregg’s Ash
Fraxinus greggii
Small, semi-evergreen tree or large shrub (evergreen in warm locations), reaching about 10-20’ high and wide. Blooms in spring with very tiny, clustered flowers with male parts appearing before female, avoiding self-pollination. Flowers followed by a samara if there is more than one plant around blooming.
Grow in full to part sun, with moderate to low water, hardy to 10°F.
Native to west Texas, New Mexico, and Arizona, south into Jalisco and Veracruz in Mexico, this large evergreen shrub grows at lower elevations along arroyos and on bluffs, talus slopes, arroyos and canyons.