Common Ninebark
Physocarpus opulifolius
Rosaceae · broadleaf deciduous shrub · native
Last updated
This profile synthesizes data from multiple published sources. Expert field review is in progress.
Physocarpus opulifolius (Rosaceae) is a deciduous shrub native to eastern North America. It grows 5 to 10 feet tall with arching branches and attractive exfoliating bark. White to pinkish flower clusters appear in late spring. The species has become one of the most popular landscape shrubs through its colorful-foliage cultivars.
Common ninebark grows in full sun to part shade on a range of soils. Cultivars dominate the trade: 'Diabolo' (8 feet, deep purple foliage), 'Center Glow' (gold center aging to burgundy), 'Coppertina' (copper-orange new growth), and 'Little Devil' (4 feet, compact purple). Powdery mildew is the primary disease concern. Hardy in Zones 2a to 8b.
Quick Facts
Phenological Calendar
As of April 23, 2026, Puget Sound stations range from 1434.4 to 1592.7 GDD₃₂. Common Ninebark typically reaches 'first bloom' at 1697 GDD₃₂, predicted around May 1.
Regional Season Tracker
GDD₃₂ accumulation across 7 Puget Sound stations · as of Apr 23, 2026| Station | GDD₃₂ | Current Stage | Next | To Go |
|---|---|---|---|---|
| Issaquah / East King | 1,593 | Pre-season | 'First bloom' | 104 |
| Seattle / UW | 1,554 | Pre-season | 'First bloom' | 143 |
| Kent / Auburn | 1,537 | Pre-season | 'First bloom' | 160 |
| Olympia / Tumwater | 1,505 | Pre-season | 'First bloom' | 193 |
| Bellingham / Whatcom | 1,483 | Pre-season | 'First bloom' | 214 |
| Tacoma / Puyallup | 1,472 | Pre-season | 'First bloom' | 225 |
| Sequim / Rain Shadow | 1,434 | Pre-season | 'First bloom' | 263 |
| Stage | GDD32 | Typical Window |
|---|---|---|
| ○ 'First bloom' BBCH '61' NEXT | 1697 | '' est. May 1 (forecast) |
| 'Full bloom' BBCH '65' | 1932 | '' est. May 10 (avg) |
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 23, 2026. Predicted dates use 16-day weather forecast through May 9, 2026, then climate normals.