Northern Lights Forsythia
Full bloomForsythia x intermedia
Oleaceae · [VERIFY] · introduced
Last updated
Deciduous shrub growing 6 to 8 feet tall with bright yellow four-lobed flowers covering arching stems in early spring before leaf emergence. Foliage is medium green; form is loose and spreading.
Hardy, low-maintenance spring accent shrub thriving in full sun to light shade and adaptable soils. Prune after flowering to shape; old canes can be removed at the base. No significant pests or diseases; tends toward leggy growth without selective pruning.
Plant Profile
Site Requirements
Ornamental Interest
Phenological Calendar
As of June 4, 2026, Puget Sound stations range from 2458.5 to 2700.8 GDD₃₂. Northern Lights Forsythia has passed full bloom (686 GDD₃₂).
Regional Season Tracker
GDD₃₂ accumulation across 7 Puget Sound stations · as of Jun 4, 2026| Station | GDD₃₂ | Current Stage | Next | To Go |
|---|---|---|---|---|
| Issaquah / East King | 2,701 | Full bloom | — | — |
| Kent / Auburn | 2,695 | Full bloom | — | — |
| Seattle / UW | 2,637 | Full bloom | — | — |
| Olympia / Tumwater | 2,598 | Full bloom | — | — |
| Tacoma / Puyallup | 2,564 | Full bloom | — | — |
| Bellingham / Whatcom | 2,560 | Full bloom | — | — |
| Sequim / Rain Shadow | 2,459 | Full bloom | — | — |
View full calendar (2 stages)
| Stage | GDD32 | Typical Window |
|---|---|---|
| Beginning of flowering BBCH 61 | 423 | — |
| ● Full bloom BBCH 65 NOW | 686 | — |
Source: UMD: extension.umd.edu) About GDD₃₂ →
Season tracker for Kent / Auburn as of Jun 4, 2026. Predicted dates use 16-day weather forecast through Jun 20, 2026, then climate normals.