Saucer Magnolia
Magnolia x soulangeana
Magnoliaceae · [VERIFY] · introduced
Last updated
Magnolia x soulangeana (Magnoliaceae) is a hybrid between M. denudata and M. liliiflora, and the most widely planted ornamental magnolia worldwide. It forms a spreading deciduous tree or large multi-stemmed shrub. The large, goblet-shaped flowers appear on bare branches in early spring, typically white to pink to purple depending on the cultivar.
Saucer magnolia performs well in full sun to part shade on moist, well-drained, acidic soil. Bloom begins around 96 GDD (base 50 F) with full bloom near 174 GDD, making it one of the earliest spring-flowering trees. The flowers are vulnerable to late frost. It blooms on old wood and should be pruned after flowering. Many named cultivars exist, ranging from nearly white to deep purple-pink.
Quick Facts
Phenological Calendar
Regional Season Tracker
GDD₃₂ accumulation across 7 Puget Sound stations · as of Mar 30, 2026| Station | GDD₃₂ | Current Stage | Next | To Go |
|---|---|---|---|---|
| Issaquah / East King | 1,116 | Full bloom | — | — |
| Seattle / UW | 1,112 | Full bloom | — | — |
| Olympia / Tumwater | 1,049 | Full bloom | — | — |
| Kent / Auburn | 1,048 | Full bloom | — | — |
| Bellingham / Whatcom | 1,041 | Full bloom | — | — |
| Tacoma / Puyallup | 1,017 | Full bloom | — | — |
| Sequim / Rain Shadow | 1,012 | Full bloom | — | — |
| Stage | GDD32 | Typical Window |
|---|---|---|
| Beginning of flowering BBCH 61 | 701 | — |
| ● Full bloom BBCH 65 NOW | 1009 | — |
GDD = Growing Degree Days (base 32°F, Jan 1 start). Why base 32? Source GDD₅₀ thresholds from Herms 2004 (OSU, Secrest Arboretum, Ohio) and UMD IPMnet (Gill & Klick, mid-Atlantic), converted to GDD₃₂ via Kent bloom-date mapping. Season tracker for Kent / Auburn as of Mar 30, 2026. Predicted dates use 16-day weather forecast through Apr 15, 2026, then climate normals.