Washington Hawthorn
Crataegus phaenopyrum
Rosaceae · broadleaf deciduous tree · native
Last updated
This profile synthesizes data from multiple published sources. Expert field review is in progress.
Washington hawthorn (Crataegus phaenopyrum, Rosaceae) is a deciduous tree native to the central United States from Missouri to Maryland and south to Louisiana and Florida. It reaches 15 to 30 feet tall with a spread of about 32 feet. It is the last hawthorn species to flower, producing delicate white blooms with pink anthers in June. Bright red, glossy fruit (6 to 8 millimeters, 3 to 5 nutlets per fruit) persists through winter. Fall color is orange to scarlet.
Washington hawthorn grows in full sun on moist soils (pH 4.3 to 7.0) with moderate water needs and a growth rate of moderate, hardy in Zones 3a to 8b. It reaches about 25 feet at 20 years and tolerates urban conditions. Disease and pest associations match the genus: 7 disease and 14 pest associations documented. No cultivars are documented. Its ornamental value comes from the combination of late bloom, persistent glossy fruit, and vivid fall color.
Quick Facts
Phenological Calendar
As of April 24, 2026, Puget Sound stations range from 1455.1 to 1613.4 GDD₃₂. Washington Hawthorn typically reaches bloom start at 2413 GDD₃₂, predicted around May 31.
Regional Season Tracker
GDD₃₂ accumulation across 7 Puget Sound stations · as of Apr 24, 2026| Station | GDD₃₂ | Current Stage | Next | To Go |
|---|---|---|---|---|
| Issaquah / East King | 1,613 | Pre-season | Bloom start | 800 |
| Seattle / UW | 1,574 | Pre-season | Bloom start | 839 |
| Kent / Auburn | 1,559 | Pre-season | Bloom start | 854 |
| Olympia / Tumwater | 1,524 | Pre-season | Bloom start | 890 |
| Bellingham / Whatcom | 1,504 | Pre-season | Bloom start | 909 |
| Tacoma / Puyallup | 1,492 | Pre-season | Bloom start | 921 |
| Sequim / Rain Shadow | 1,455 | Pre-season | Bloom start | 958 |
| Stage | GDD32 | Typical Window |
|---|---|---|
| ○ Bloom start BBCH 61 NEXT | 2413 | Apr 1-Apr 30 est. May 31 (avg) |
| Full bloom BBCH 65 | 2485 | — est. Jun 3 (avg) |
| Bud break BBCH 07 | — | Feb 15-Mar 15 |
| Leaf emergence BBCH 11 | — | 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 |
GDD = Growing Degree Days (base 32°F, Jan 1 start). Why base 32? Source GDD₅₀ thresholds from Herms 2004 (OSU, Secrest Arboretum, Ohio) and UMD IPMnet (Gill & Klick, mid-Atlantic), converted to GDD₃₂ via Kent bloom-date mapping. Season tracker for Kent / Auburn as of Apr 24, 2026. Predicted dates use 16-day weather forecast through May 10, 2026, then climate normals.