Oregon Ash
Fraxinus latifolia · Deciduous, Broadleaf, Hardwood
Plant Family
Oleaceae
Tree Category
Shade Tree, Riparian Forest Tree
Variety / Cultivar
Standard species
Hardiness Zones
USDA Zones 6-9; well-adapted to Pacific Northwest coastal and valley climates.
About This Tree
A medium to large deciduous tree with a broad, rounded crown and stout branches. It has a sympodial branching pattern and a dense canopy that provides excellent shade. It is characterized by its rapid growth in moist environments and its adaptability to heavy clay soils.
Leaf Characteristics
Opposite, pinnately compound leaves typically 5-11 inches long with 5-7 leaflets. Leaflets are oval to oblong, light green to medium green, with slightly serrated or smooth margins and velvety undersides.
Bark Characteristics
Dark gray to brownish-gray; on mature trees, the bark becomes deeply furrowed with a networking pattern of flat-topped ridges, often forming a diamond-like pattern.
Growing Information
Origin Region
Native to Western North America (British Columbia to Central California)
Growing Season
Leafs out in late spring (one of the last to leaf out), flowers in April-May before leaves appear, samara fruits ripen in late summer, and enters dormancy in late autumn with yellow fall color.
Sunlight & Water Needs
Full Sun to Partial Shade. High water needs; thrives in moist to wet soils but can tolerate moderate drought once established in deep soils.
Mature Size
Mature height of 60-80 feet with a canopy spread of 30-50 feet. Moderate to fast growth rate; can live up to 150-250 years.
Special Characteristics
Highly tolerant of seasonal flooding and heavy saturated soils. Provides valuable timber for handles and furniture. Highly susceptible to the invasive Emerald Ash Borer.
Wildlife & Ecology
Provides essential habitat for wood ducks and cavity-nesting birds. The winged seeds (samaras) are a food source for squirrels, grosbeaks, and other birds. It serves as a host plant for Western Tiger Swallowtail larvae.