Persian Lilac
Syringa persica
Oleaceae · broadleaf deciduous shrub · introduced
Last updated
Data Coverage 3 of 6 dimensions
Quick Facts
Height
4–8 ft
Light
Full Sun to Part Shade
Hardiness
Zone Zones 5a–8b
Phenological Calendar
As of April 3, 2026, Puget Sound stations range from 1070 to 1180.6 GDD₃₂. Persian Lilac has reached 'first bloom' (1080 GDD₃₂) and is approaching 'full bloom', predicted around Apr 16.
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' | 183 |
| Seattle / UW | 1,171 | 'First bloom' | 'Full bloom' | 193 |
| Kent / Auburn | 1,111 | 'First bloom' | 'Full bloom' | 253 |
| Olympia / Tumwater | 1,106 | 'First bloom' | 'Full bloom' | 258 |
| Bellingham / Whatcom | 1,101 | 'First bloom' | 'Full bloom' | 263 |
| Tacoma / Puyallup | 1,075 | Pre-season | 'First bloom' | 5 |
| Sequim / Rain Shadow | 1,070 | Pre-season | 'First bloom' | 10 |
| Stage | GDD32 | Typical Window |
|---|---|---|
| ● 'First bloom' BBCH '61' NOW | 1080 | '' |
| ○ 'Full bloom' BBCH '65' NEXT | 1364 | '' est. Apr 16 (forecast) |
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.