White Ash
Leaf emergenceFraxinus americana
Oleaceae · broadleaf deciduous tree · introduced
Last updated
White ash (Fraxinus americana, Oleaceae) is a moderate-growing deciduous tree native to eastern North America from Nova Scotia to Minnesota and south to Florida and Texas, reaching 50 to 80 feet with a spread of about 49 feet. Opposite, pinnate compound leaves (20 to 38 centimeters) bear 5 to 9 leaflets (usually 7) that are dark green above with distinctive glaucous undersides. Fall color ranges from yellow to maroon to deep purple. Dioecious flowers lack petals and appear before leaves in April to May.
White ash grows in full sun on wet-tolerant soils (pH 4.7 to 7.5) with high water needs and low drought tolerance, hardy in Zones 4a to 8b. It reaches about 40 feet at 20 years. Documented diseases (8 total) include Nectria canker, anthracnose, and verticillium wilt. Pest associations (9 total) include ash borer, carpenterworm, and lecanium scale. The emerald ash borer, present in Oregon and devastating to all Fraxinus species, is the dominant threat. The cultivar 'Autumn Purple' (seedless male clone, deep purple-red fall color) is the primary selection.
Plant Profile
Size & Form
Site Requirements
Ornamental Interest
Field Observations
Root Colonization Period
Peak Population & Dispersal
Larval Feeding & Web Building
Crawler Emergence
+ 5 more — see full disease and pest lists below
Diseases: Regionally Documented (8)
Pests: Regionally Documented (8)
Pests: Other Associations (1)
Phenological Calendar
As of June 3, 2026, Puget Sound stations range from 2435.5 to 2672.8 GDD₃₂. White Ash has passed leaf emergence (1539 GDD₃₂).
Regional Season Tracker
GDD₃₂ accumulation across 7 Puget Sound stations · as of Jun 3, 2026| Station | GDD₃₂ | Current Stage | Next | To Go |
|---|---|---|---|---|
| Issaquah / East King | 2,673 | Leaf emergence | — | — |
| Kent / Auburn | 2,665 | Leaf emergence | — | — |
| Seattle / UW | 2,610 | Leaf emergence | — | — |
| Olympia / Tumwater | 2,570 | Leaf emergence | — | — |
| Tacoma / Puyallup | 2,535 | Leaf emergence | — | — |
| Bellingham / Whatcom | 2,533 | Leaf emergence | — | — |
| Sequim / Rain Shadow | 2,436 | Leaf emergence | — | — |
View full calendar (9 stages)
| Stage | GDD32 | Typical Window |
|---|---|---|
| Bloom start BBCH 61 | 1102 | Apr 1-Apr 30 |
| Full bloom BBCH 65 | 1080 | — |
| Bud break BBCH 07 | — | Feb 15-Mar 15 |
| ● Leaf emergence BBCH 11 NOW | 1539 Observed | Mar 1-Apr 1 |
| Bloom end / petal fall BBCH 69 | — | Apr 15-May 15 |
| Fruit/seed development BBCH 71 | — | Jun 1-Aug 31 |
| Fruit/seed maturity BBCH 85 | — | Sep 1-Nov 30 |
| Fall color / leaf senescence BBCH 93 | — | Oct 1-Nov 15 |
| Dormancy BBCH 97 | — | Nov 15-Feb 28 |
Sources: USDA Plants Database (seasonal estimate) ; OSU phenology catalog (OSU: weather.cfaes.osu.edu) ; Field observation, Kent area, 2026-04-23 About GDD₃₂ →
Season tracker for Kent / Auburn as of Jun 3, 2026. Predicted dates use 16-day weather forecast through Jun 19, 2026, then climate normals.