Red Buckeye
Aesculus pavia
Sapindaceae, Hippocastanaceae · broadleaf deciduous shrub · native
Last updated
Data Coverage 5 of 6 dimensions
Quick Facts
Height
10-20 ft
Spread
9 ft
Growth Rate
Fast
Light
Full Sun to Shade
Soil
Moist
Water
Moderate
Hardiness
Zone Zones 5a–8b
Bloom Time
April to May
Origin
extends from Virginia to Florida and east to Louisiana and
Phenological Calendar
As of April 3, 2026, Puget Sound stations range from 1070 to 1180.6 GDD₃₂. Red Buckeye has reached 'first bloom' (973 GDD₃₂) and is approaching 'full bloom', predicted around Apr 9.
Regional Season Tracker
GDD₃₂ accumulation across 7 Puget Sound stations · as of Apr 3, 2026| Station | GDD₃₂ | Current Stage | Next | To Go |
|---|---|---|---|---|
| Issaquah / East King | 1,181 | 'First bloom' | 'Full bloom' | 48 |
| Seattle / UW | 1,171 | 'First bloom' | 'Full bloom' | 58 |
| Kent / Auburn | 1,111 | 'First bloom' | 'Full bloom' | 118 |
| Olympia / Tumwater | 1,106 | 'First bloom' | 'Full bloom' | 123 |
| Bellingham / Whatcom | 1,101 | 'First bloom' | 'Full bloom' | 128 |
| Tacoma / Puyallup | 1,075 | 'First bloom' | 'Full bloom' | 154 |
| Sequim / Rain Shadow | 1,070 | 'First bloom' | 'Full bloom' | 159 |
| Stage | GDD32 | Typical Window |
|---|---|---|
| ● 'First bloom' BBCH '61' NOW | 973 | '' |
| ○ 'Full bloom' BBCH '65' NEXT | 1229 | '' est. Apr 9 (forecast) |
Range: 728–874 GDD₃₂
(6yr)
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 3, 2026. Predicted dates use 16-day weather forecast through Apr 19, 2026, then climate normals.
Diseases (3)
Cultivars (1)
'Humilis'
Common name: Dwarf Red Buckeye; Mature height: 15 ft