Silk Tree
Albizia julibrissin
Fabaceae · broadleaf deciduous tree · introduced
Last updated
Quick Facts
Height
20–30 ft
Spread
32 ft
Growth Rate
Fast
Light
Full Sun
Soil
Wet Tolerant
Water
Moderate
Hardiness
Zone Zones 6a–8b
Bloom Time
June to July
Fall Color
Insignificant
Origin
from Iran to central China
Phenological Calendar
As of May 13, 2026, Puget Sound stations range from 1906.2 to 2098.2 GDD₃₂. Silk Tree typically reaches 'first bloom' at 3165 GDD₃₂, predicted around Jun 22.
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 | Pre-season | 'First bloom' | 1,067 |
| Kent / Auburn | 2,089 | Pre-season | 'First bloom' | 1,076 |
| Seattle / UW | 2,063 | Pre-season | 'First bloom' | 1,102 |
| Olympia / Tumwater | 2,025 | Pre-season | 'First bloom' | 1,140 |
| Tacoma / Puyallup | 1,993 | Pre-season | 'First bloom' | 1,172 |
| Bellingham / Whatcom | 1,972 | Pre-season | 'First bloom' | 1,193 |
| Sequim / Rain Shadow | 1,906 | Pre-season | 'First bloom' | 1,259 |
| Stage | GDD32 | Typical Window |
|---|---|---|
| ○ 'First bloom' BBCH '61' NEXT | 3165 | '' est. Jun 22 (avg) |
| 'Full bloom' BBCH '65' | 3665 | '' est. Jul 9 (avg) |
Range: 2711–3098 GDD₃₂
(6yr)
Source: 'Master catalog (UMD), converted GDD50->GDD32 via Kent bloom-date mapping' 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.
Cultivars (1)
'Summer Chocolate' Summer Chocolate®
Common name: Summer Chocolate Silk Tree; Mature height: 20 ft
Hardy to USDA Zone 6
Data Maturity Structured Multiple sources. Expert review underway.