Blackhaw Viburnum
'Full bloom'Viburnum prunifolium
Adoxaceae, Caprifoliaceae · broadleaf deciduous shrub · introduced
Last updated
Plant Profile
Size & Form
Height
12–15 ft
Spread
16 ft
Growth Rate
Slow
Site Requirements
Light
Full Sun
Soil Drainage
Moist
Soil pH
4.5-8.5
Water
Moderate
Hardiness
Zones 3a–8b
Ornamental Interest
Bloom Time
May to June
Fall Color
Red
Origin
from Connecticut to Florida, west to Michigan and Texas
Watch for this season
Powdery MildewHigh
Active Conidial Spread
Larval Hatching & Feeding
Root weevilModerate
Adult Emergence & Foliar Feeding
Diseases: Regionally Documented (7)
Pests: Regionally Documented (3)
Phenological Calendar
As of June 3, 2026, Puget Sound stations range from 2435.5 to 2672.8 GDD₃₂. Blackhaw Viburnum has passed 'full bloom' (1200 GDD₃₂).
Regional Season Tracker
GDD₃₂ accumulation across 7 Puget Sound stations · as of Jun 3, 2026| Station | GDD₃₂ | Current Stage | Next | To Go |
|---|---|---|---|---|
| Issaquah / East King | 2,673 | 'Full bloom' | — | — |
| Kent / Auburn | 2,665 | 'Full bloom' | — | — |
| Seattle / UW | 2,610 | 'Full bloom' | — | — |
| Olympia / Tumwater | 2,570 | 'Full bloom' | — | — |
| Tacoma / Puyallup | 2,535 | 'Full bloom' | — | — |
| Bellingham / Whatcom | 2,533 | 'Full bloom' | — | — |
| Sequim / Rain Shadow | 2,436 | 'Full bloom' | — | — |
View full calendar (2 stages)
| 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 Jun 3, 2026. Predicted dates use 16-day weather forecast through Jun 19, 2026, then climate normals.
Data Maturity Structured Multiple sources. Expert review underway.