Blackhaw Viburnum
'Full bloom'Viburnum prunifolium
Adoxaceae, Caprifoliaceae · broadleaf deciduous shrub · native
Last updated
Quick Facts
Height
12–15 ft
Spread
16 ft
Growth Rate
Slow
Light
Full Sun
Soil
Moist
Water
Moderate
Hardiness
Zone Zones 3a–8b
Bloom Time
May to June
Fall Color
Red
Origin
from Connecticut to Florida, west to Michigan and Texas
Watch for this season
Powdery MildewModerate
Spring Emergence / Primary Infection
Root weevilModerate
Adult Emergence & Foliar Feeding
Phenological Calendar
As of May 14, 2026, Puget Sound stations range from 1926.1 to 2121.1 GDD₃₂. Blackhaw Viburnum has passed 'full bloom' (1200 GDD₃₂).
Regional Season Tracker
GDD₃₂ accumulation across 7 Puget Sound stations · as of May 14, 2026| Station | GDD₃₂ | Current Stage | Next | To Go |
|---|---|---|---|---|
| Issaquah / East King | 2,121 | 'Full bloom' | — | — |
| Kent / Auburn | 2,113 | 'Full bloom' | — | — |
| Seattle / UW | 2,085 | 'Full bloom' | — | — |
| Olympia / Tumwater | 2,047 | 'Full bloom' | — | — |
| Tacoma / Puyallup | 2,016 | 'Full bloom' | — | — |
| Bellingham / Whatcom | 1,994 | 'Full bloom' | — | — |
| Sequim / Rain Shadow | 1,926 | 'Full bloom' | — | — |
| Stage | GDD32 | Typical Window |
|---|---|---|
| 'First bloom' BBCH '61' | 1008 | '' |
| ● 'Full bloom' BBCH '65' NOW | 1200 | '' |
Range: 768–918 GDD₃₂
(6yr)
Source: 'Master catalog (OSU), converted GDD50->GDD32 via Kent bloom-date mapping' About GDD₃₂ →
Season tracker for Kent / Auburn as of May 14, 2026. Predicted dates use 16-day weather forecast through May 30, 2026, then climate normals.
Diseases: Regionally Documented (7)
Pests: Regionally Documented (3)
Data Maturity Structured Multiple sources. Expert review underway.