Scientific: Fraxinus velutina (some consider a subspecies of Faxinus pennsylvanica Marsh., as ssp. velutina (Torr) G. N. Miller.)
Common: Arizona ash, also called velvet ash, desert ash, leather leaf ash, smooth ash, Toumey ash, Fresno ash, Modesto ash.
Family: Oleaceae
Origin: Found in foothills and lower mountain canyons of Southwest America from California to Texas and north
into canyons and riverbanks of southcentral Utah and southern Nevada. Also found in Coahuila and Tamaulipas, Mexico. In Arizona, native to riparian areas between 3,500 and 7,000 feet elevation.
Pronounciation: FRAX-i-nus vel-u-TEE-na
Hardiness zones
Sunset 8-9, 12-24
USDA 6-11
Landscape Use: Deciduous shade tree, residential and commercial mesic landscape design themes, lawn tree.
Form & Character: Upright, rounded and open, clean looking, stately, but not majestic like Fraxinus uhdei; seasonally changing.
Growth Habit: Deciduous, woody, broadleaf perennial tree, moderate growth rate to 40-feet tall with an equal spread depending on cultivar. Arizona ash can grow to 70-feet tall in coastal valleys of California.
Foliage/Texture: Dark green, glabrous, pinnately compound leaves, mostly 5 ovate to lanceolate leaflets per leaf, leaf margin slightly serrate, trunk and branches smooth and light gray when young changing to rough and dark with age; medium texture.
Flowers & Fruits: Dioecious, flowers inconspicuously grown on separate trees in late winter just before or at leaf emergence; fruits are winged achenes.
Seasonal Color: Flaming golden yellow fall color (on the banks of the Sevier River in south central Utah) during October to January depending on site location and elevation; mostly December in Phoenix.
Temperature: Arizona ash is tolerant of desert heat only if the canopy is full, vigorous and spreading. If not a full and vigorous canopy of foliage, then Arizona ash is prone to trunk sunscald if exposed to desert summer temperatures plus direct and/or reflected western sunlight.
Light: Full sun, although I feel led to repeat myself 'like a broken record' that Arizona ash is highly susceptible to trunk scald from western sun in Phoenix if its canopy of leaves is 'skimpy'.
Soil: Tolerates alkaline, desert soils.
Watering: Arizona ash is the quintessential mesic tree in Phoenix requiring regular applications of supplemental water for best performance.
Pruning: Elevate canopy base (raise the crown base) only slowly over time only as high as needed. Young trees do not need staking. In Phoenix, DO NOT crown thin Arizona ash trees in Phoenix!! Do this and it's the 'Kiss of Death'.
Propagation: Cutting, grafting or budding
Disease and Pests: Scale and aphids are minor cosmetic problems that appear on ash tree foliage only during early spring. Ash decline (Phytoplasma organism) in contrast is a progressive, lethal problem that will generally slowly kill otherwise healthy trees over a 5 to 10 year time span. In Phoenix, ash decline is mostly localized in pockets around the metropolitan region spreading geographically relatively slowly. Symptoms of this disease are leaf discoloration and small branch dieback showing each year in mid summer. There is no cure for this disease and Arizona ash trees with ash decline should be well fertilized and irrigated to prolong their eventual demise.
Special disease note: Fraxinus oxycarpa (Raywood ash) is also highly susceptible to ash decline, but Fraxinus uhdei (Shamel ash) is not.
Additional comments: In Phoenix, Arizona ash gives a dependable show of yellow to golden yellow fall color during late November and December; however, its use in Phoenix landscapes is dictated by the local presence of Ash decline. If Ash decline is present in surrounding neighborhoods, then I would not recommend the planting of an Arizona ash.
Popular Arizona ash cultivars include:
There are several other cultivated variants and hybrids with Arizona ash parentage that are relatively new to the Phoenix landscape industry. One of these is Fraxinus pennsylvanica x Fraxinus velutina 'Fan-West' (Fan-West ash). It's reported to be a seedless hybrid having light olive green leaves on a good limb-head structure. It is an upright and rounded form with seven olive-green leaflets per leaf. It was found by Eddie Fanick of San Antonio, Texas as a natural seedling on the banks of the Guadalupe River in Texas. Most 'ash geeks' think this tree resembles Fraxinus pennsylvanica more than Fraxinus velutina. For propagation, Fan-West ash is usually budded onto Fraxinus velutina seedling rootstock.
