Red Flowering Horsechestnut
Aesculus carnea
Sapindaceae, Hippocastanaceae · broadleaf deciduous tree · introduced
Last updated
Quick Facts
Height
35–50 ft
Light
Full Sun to Shade
Hardiness
Zones 4–5
Phenological Calendar
As of May 24, 2026, Puget Sound stations range from 2172.5 to 2394 GDD₃₂. Red Flowering Horsechestnut has passed 'full bloom' (1672 GDD₃₂).
Regional Season Tracker
GDD₃₂ accumulation across 7 Puget Sound stations · as of May 24, 2026| Station | GDD₃₂ | Current Stage | Next | To Go |
|---|---|---|---|---|
| Issaquah / East King | 2,394 | 'Full bloom' | — | — |
| Kent / Auburn | 2,373 | 'Full bloom' | — | — |
| Seattle / UW | 2,332 | 'Full bloom' | — | — |
| Olympia / Tumwater | 2,295 | 'Full bloom' | — | — |
| Tacoma / Puyallup | 2,259 | 'Full bloom' | — | — |
| Bellingham / Whatcom | 2,256 | 'Full bloom' | — | — |
| Sequim / Rain Shadow | 2,173 | 'Full bloom' | — | — |
View full calendar (2 stages)
| Stage | GDD32 | Typical Window |
|---|---|---|
| 'First bloom' BBCH '61' | 1368 | '' |
| ● 'Full bloom' BBCH '65' NOW | 1672 | '' |
Source: 'Master catalog (OSU, UMD), GDD50 base' About GDD₃₂ →
Season tracker for Kent / Auburn as of May 24, 2026. Predicted dates use 16-day weather forecast through Jun 9, 2026, then climate normals.
Cultivars (1)
'Oneill Red'
Common name: O'Neill Red Horsechestnut O'Neil Horsechestnut; Mature height: 35 ft
Data Maturity Baseline Extension data. Expert review underway.