Chinese Lilac Rouen Lilac
'First bloom'Syringa chinensis
Oleaceae · broadleaf deciduous shrub · introduced
Last updated
Quick Facts
Height
8–15 ft
Growth Rate
Medium
Light
Full Sun to Part Shade
Soil
Well Drained
Water
Moderate
Hardiness
Zone Zones 3a–8b
Fall Color
Purple
Watch for this season
Bacterial BlightHigh
Spring Infection Period
Oystershell scaleHigh
Crawler Emergence
Powdery MildewModerate
Spring Emergence / Primary Infection
Root weevilModerate
Adult Emergence & Foliar Feeding
Phenological Calendar
As of May 13, 2026, Puget Sound stations range from 1906.2 to 2098.2 GDD₃₂. Chinese Lilac Rouen Lilac has passed 'first bloom' (1182 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 | 'First bloom' | — | — |
| Kent / Auburn | 2,089 | 'First bloom' | — | — |
| Seattle / UW | 2,063 | 'First bloom' | — | — |
| Olympia / Tumwater | 2,025 | 'First bloom' | — | — |
| Tacoma / Puyallup | 1,993 | 'First bloom' | — | — |
| Bellingham / Whatcom | 1,972 | 'First bloom' | — | — |
| Sequim / Rain Shadow | 1,906 | 'First bloom' | — | — |
| Stage | GDD32 | Typical Window |
|---|---|---|
| 'Bud break' BBCH '07' | 511 | '' |
| ● 'First bloom' BBCH '61' NOW | 1182 | '' |
Source: 'NPN citizen science observations (WA+OR), n=18, 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 (7)
Multiple obligate biotrophic fungi (Erysiphales: Erysipha... Powdery Mildew Pseudomonas syringae pv. syringae Bacterial Blight Gray Mold Symptom category — not a single disease Leaf Spot Lilac ring mottle virus Lilac Ring Mottle Phytophthora Canker and Shoot Blight Symptom category — not a single disease Root Rot
Pests: Regionally Documented (4)
Cultivars (1)
'Lilac Sunday'
Common name: Lilac Sunday Lilac; Mature height: 12 ft
Hardy to USDA Zone 3
Data Maturity Structured Multiple sources. Expert review underway.