Ash
Sorbaria sorbifolia
Rosaceae · broadleaf · introduced
Last updated
Data Coverage 4 of 6 dimensions
Quick Facts
Height
6 ft
Spread
9 ft
Growth Rate
Fast
Light
Sun to Part Shade
Soil
Moist
Water
Moderate
Hardiness
Zone Zones 2a–7b
Bloom Time
June to July
Phenological Calendar
Regional Season Tracker
GDD₃₂ accumulation across 7 Puget Sound stations · as of Mar 22, 2026| Station | GDD₃₂ | Current Stage | Next | To Go |
|---|---|---|---|---|
| Seattle / UW | 1,013 | Pre-season | Beginning of flowering | 2,263 |
| Issaquah / East King | 1,006 | Pre-season | Beginning of flowering | 2,270 |
| Olympia / Tumwater | 952 | Pre-season | Beginning of flowering | 2,324 |
| Bellingham / Whatcom | 948 | Pre-season | Beginning of flowering | 2,328 |
| Kent / Auburn | 942 | Pre-season | Beginning of flowering | 2,334 |
| Sequim / Rain Shadow | 924 | Pre-season | Beginning of flowering | 2,352 |
| Tacoma / Puyallup | 921 | Pre-season | Beginning of flowering | 2,355 |
| Stage | GDD32 | Typical Window |
|---|---|---|
| ○ Beginning of flowering BBCH 61 NEXT | 3276 | — est. Jul 4 (avg) |
Range: 2515–2896 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 Mar 22, 2026. Predicted dates use 16-day weather forecast through Apr 7, 2026, then climate normals.
Cultivars (2)
''Bococot'' Cherry On Top™
Cherry On Top™ Sorbaria, Cherry On Top™ Ash Leaf Spiraea
''Sem''
Sem Ash Leaf Spiraea