Blackhaw Viburnum
Viburnum prunifolium
Adoxaceae, Caprifoliaceae · broadleaf deciduous shrub · native
Last updated
Data Maturity Structured
This profile synthesizes data from multiple published sources. Expert field review is in progress.
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
Phenological Calendar
As of April 24, 2026, Puget Sound stations range from 1455.1 to 1613.4 GDD₃₂. Blackhaw Viburnum has passed 'full bloom' (1200 GDD₃₂).
Regional Season Tracker
GDD₃₂ accumulation across 7 Puget Sound stations · as of Apr 24, 2026| Station | GDD₃₂ | Current Stage | Next | To Go |
|---|---|---|---|---|
| Issaquah / East King | 1,613 | 'Full bloom' | — | — |
| Seattle / UW | 1,574 | 'Full bloom' | — | — |
| Kent / Auburn | 1,559 | 'Full bloom' | — | — |
| Olympia / Tumwater | 1,524 | 'Full bloom' | — | — |
| Bellingham / Whatcom | 1,504 | 'Full bloom' | — | — |
| Tacoma / Puyallup | 1,492 | 'Full bloom' | — | — |
| Sequim / Rain Shadow | 1,455 | 'Full bloom' | — | — |
| Stage | GDD32 | Typical Window |
|---|---|---|
| 'First bloom' BBCH '61' | 1008 | '' |
| ● 'Full bloom' BBCH '65' NOW | 1200 | '' |
Range: 768–918 GDD₃₂
(6yr)
GDD = Growing Degree Days (base 32°F, Jan 1 start). Why base 32? Hover over GDD values for source details. Season tracker for Kent / Auburn as of Apr 24, 2026. Predicted dates use 16-day weather forecast through May 10, 2026, then climate normals.
Diseases (8)
Symptom category — not a single disease Leaf Spot Botrytis Shoot Blight Ramorum Blight (Sudden Oak Death) Multiple obligate biotrophic fungi (Erysiphales: Erysipha... Powdery Mildew Bacterial blight (Leaf spot) Symptom category — not a single disease Root Rot Phytophthora cactorum"heeled in\" (placed in sawdust pile... Shoot Blight Botryosphaeria corticis Stem Canker