Fraxinus americana - White Ash
Family: Oleaceae

Hear the scientific name

Fraxinus americana is a broad-spreading, large shade tree of moderate growth rate. White Ash has excellent autumn foliage, bark character and bold texture in winter but is not urban tolerant.

F   E   A   T   U   R   E   S
  form Form

-large deciduous tree

-maturing at 70' tall x 70' wide

-upright rounded growth habit

-medium growth rate

foliage Foliage

-opposite arrangement, medium to dark green and pinnately compound, casting a dense shade

-leaflets (usually 7) are ovate and usually entire on the margins

-autumn color - vivid orange, yellow, maroon, red, purple, or combinations thereof, usually in late Sept. and completely abscised by mid-Oct.

Flowers

-dioecious (male and female trees)

-green to purple inflorescences in Apr. are not especially showy

Fruit

-green changing to brown clusters of samaras on female trees, littering the ground or gutters with winged seeds in autumn

Twig
twig

-thick and stout stems are olive changing to brown and lenticeled

-leaf scars are U-shaped with the brown pubescent lateral buds resting within the leaf scar

trunk Trunk

-gray-brown and smooth in youth, becoming very deeply furrowed and ridged in a few short years, with the ridges interlacing to form a diamondback pattern of 2" thick bark with age

-smooth gray bark persists in larger diameter branches than in Green Ash (Fraxinus pennsylvanica)

-quickly losing its central leader to yield several large upright or spreading branches for a very rounded habit

C   U   L   T   U   R   E
 

Culture

-full sun

-adaptable to soil types and soil pHs but overall not especially urban tolerant (especially to soil compaction, drought and air pollution)

-propagated by cuttings grafted onto seedling understock

-Olive Family, with several disease (leaf spots, branch cankers, mycoplasma-induced decline and dieback) and pest (oyster shell scale and wood borer) problems

-abundantly available in B&B form, including several cultivars noted for growth habit or autumn color variation

distribution map

Hardiness

-zones 3 to 9

Origin

-native to the Eastern and Midwestern U.S. and Southern Canada; a major tree of midwestern forests

U   S   A   G   E
 

Assets

-moderately quick growth for a shade tree

-brilliant autumn color

-bold texture in winter

-ornamental bark

-symmetrical rounded shape

Liabilities

-not especially urban tolerant

-some pest and disease problems, including borers

-dense shading leads to dead stem litter from the interior of the canopy

-surface roots with age

Function

-shade or specimen tree

Texture

-medium texture in foliage and bold when bare

-thick density in foliage and average when bare

S   E   L   E   C   T   I   0   N   S
 

Varieties and Cultivars - Search OSU PlantFacts for additional plants in this species

Alternates

-large shade trees and those with excellent autumn color

-large trees that grow moderately fast

 


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