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Blackhaw Viburnum

Viburnum prunifolium

Adoxaceae, Caprifoliaceae · broadleaf deciduous shrub · native

Last updated

Data Coverage 4 of 6 dimensions
Site Data
Threats
Cultivars
Phenology
GDD Thresholds
Puget Sound

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 3, 2026, Puget Sound stations range from 1070 to 1180.6 GDD₃₂. Blackhaw Viburnum has reached 'first bloom' (1008 GDD₃₂) and is approaching 'full bloom', predicted around Apr 7.

Regional Season Tracker

GDD₃₂ accumulation across 7 Puget Sound stations · as of Apr 3, 2026
Station GDD₃₂ Current Stage Next To Go
Issaquah / East King 1,181 'First bloom' 'Full bloom' 19
Seattle / UW 1,171 'First bloom' 'Full bloom' 29
Kent / Auburn 1,111 'First bloom' 'Full bloom' 89
Olympia / Tumwater 1,106 'First bloom' 'Full bloom' 94
Bellingham / Whatcom 1,101 'First bloom' 'Full bloom' 99
Tacoma / Puyallup 1,075 'First bloom' 'Full bloom' 125
Sequim / Rain Shadow 1,070 'First bloom' 'Full bloom' 130
Stage GDD32 Typical Window
● 'First bloom' BBCH '61' NOW 1008 ''
○ 'Full bloom' BBCH '65' NEXT 1200 '' est. Apr 7 (forecast)
Regional estimate
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 3, 2026. Predicted dates use 16-day weather forecast through Apr 19, 2026, then climate normals.

Diseases (10)

Pests (3)