Green Hawthorn
'Full bloom'Crataegus viridis
Rosaceae · broadleaf deciduous tree · introduced
Last updated
Plant Profile
Size & Form
Height
20–40 ft
Spread
20-35 ft
Growth Rate
Slow
Site Requirements
Light
Full Sun
Soil Drainage
Well Drained, Adaptable
Soil pH
adaptable (acidic to alkaline)
Water
Low to moderate
Drought Tolerance
Moderate to high
Hardiness
Zones 4a–8b
Ornamental Interest
Bloom Time
May
Fall Color
Purple, scarlet
Origin
from Maryland, Virginia to Illinois
Watch for this season
Fire BlightHigh
Bloom Infection Window
Powdery MildewHigh
Active Conidial Spread
RustHigh
Uredinial Stage (Summer)
Adult Flight
+ 3 more — see full disease and pest lists below
Diseases: Regionally Documented (6)
Venturia spp. — multiple host-specific species: V Scab Multiple genera (Melampsoridium, Thekopsora, Naohidemyces... Rust Symptom category — not a single disease Leaf Spot Erwinia amylovora Fire Blight Symptom category — not a single disease Canker Multiple obligate biotrophic fungi (Erysiphales: Erysipha... Powdery Mildew
Pests: Regionally Documented (10)
Tetranychidae Spider mite Coccoidea Scale insect Caliroa cerasi Pear slug Dysaphis crataegi Hawthorn aphid Choreutis pariana Apple-and-thorn skeletonizer Acanthococcus azaleae Azalea bark scale Enarmonia formosana Cherry bark tortrix Hyphantria cunea Fall webworm Tortricidae Leafroller Malacosoma spp. Tent caterpillar
Phenological Calendar
As of June 3, 2026, Puget Sound stations range from 2435.5 to 2672.8 GDD₃₂. Green Hawthorn has passed 'full bloom' (1370 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 | 'Full bloom' | — | — |
| Kent / Auburn | 2,665 | 'Full bloom' | — | — |
| Seattle / UW | 2,610 | 'Full bloom' | — | — |
| Olympia / Tumwater | 2,570 | 'Full bloom' | — | — |
| Tacoma / Puyallup | 2,535 | 'Full bloom' | — | — |
| Bellingham / Whatcom | 2,533 | 'Full bloom' | — | — |
| Sequim / Rain Shadow | 2,436 | 'Full bloom' | — | — |
View full calendar (2 stages)
| Stage | GDD32 | Typical Window |
|---|---|---|
| 'First bloom' BBCH '61' | 1200 | '' |
| ● 'Full bloom' BBCH '65' NOW | 1370 | '' |
Range: 888–1070 GDD₃₂
(6yr)
Source: 'Master catalog (OSU, UMD), converted GDD50->GDD32 via Kent bloom-date mapping' 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.
Cultivars (1)
'Winter King'
Common name: Winter King Hawthorn Winter King Green Hawthorn; Mature height: 20–25 ft
Hardy to USDA Zone 4
Data Maturity Structured Multiple sources. Expert review underway.