Black Walnut
'Flower buds visible'Juglans nigra
Juglandaceae · broadleaf deciduous tree · native
Last updated
Quick Facts
Height
100 ft
Spread
65 ft
Growth Rate
Fast
Light
Full Sun
Soil
Well Drained
Water
High
Hardiness
Zone Zones 4a–8b
Bloom Time
May to June
Fall Color
Yellow, insignificant
Origin
Massachusetts to Florida, west to Minnesota and Texas
Watch for this season
Primary Spore Release
Phytophthora Root RotModerate
Growing Season Stress Expression
Crown GallMonitor
Dormant in Soil
Phenological Calendar
As of May 13, 2026, Puget Sound stations range from 1906.2 to 2098.2 GDD₃₂. Black Walnut has passed 'flower buds visible' (1671 GDD₃₂).
Regional Season Tracker
GDD₃₂ accumulation across 7 Puget Sound stations · as of May 13, 2026| Station | GDD₃₂ | Current Stage | Next | To Go |
|---|---|---|---|---|
| Issaquah / East King | 2,098 | 'Flower buds visible' | — | — |
| Kent / Auburn | 2,089 | 'Flower buds visible' | — | — |
| Seattle / UW | 2,063 | 'Flower buds visible' | — | — |
| Olympia / Tumwater | 2,025 | 'Flower buds visible' | — | — |
| Tacoma / Puyallup | 1,993 | 'Flower buds visible' | — | — |
| Bellingham / Whatcom | 1,972 | 'Flower buds visible' | — | — |
| Sequim / Rain Shadow | 1,906 | 'Flower buds visible' | — | — |
| Stage | GDD32 | Typical Window |
|---|---|---|
| 'Bud break' BBCH '07' | 1410 | '' |
| 'Leaf emergence' BBCH '11' | 1526 | '' |
| ● 'Flower buds visible' BBCH '51' NOW | 1671 | '' |
Source: 'NPN citizen science observations (WA+OR), n=7, median. services.usanpn.org' About GDD₃₂ →
Season tracker for Kent / Auburn as of May 13, 2026. Predicted dates use 16-day weather forecast through May 29, 2026, then climate normals.
Diseases: Regionally Documented (10)
Discula destructiva (dogwood), Kabatiella and Discula spp... Anthracnose Black Walnut Toxicity Rhizobium radiobacter (formerly Agrobacterium tumefaciens) Crown Gall Pseudomicrostroma juglandis (syn. Microstroma juglandis) Downy Leaf Spot Mosses and Lichens Phytophthora spp. (P Phytophthora Root Rot Geosmithia morbida (vectored by Pityophthorus juglandis) Thousand Cankers Disease Blackline virus Blackline Pratylenchus penetrans (primary) and P Nematode, Root-lesion Xanthomonas arboricola pv. juglandis Walnut Blight
Pests: Regionally Documented (6)
Data Maturity Structured Multiple sources. Expert review underway.