Umbrella Magnolia Umbrella Tree
Magnolia tripetala
Magnoliaceae · broadleaf deciduous tree · native
Last updated
This profile synthesizes data from multiple published sources. Expert field review is in progress.
Quick Facts
Phenological Calendar
As of April 23, 2026, Puget Sound stations range from 1434.4 to 1592.7 GDD₃₂. Umbrella Magnolia Umbrella Tree has reached bloom start (1368 GDD₃₂) and is approaching full bloom, predicted around May 7.
Regional Season Tracker
GDD₃₂ accumulation across 7 Puget Sound stations · as of Apr 23, 2026| Station | GDD₃₂ | Current Stage | Next | To Go |
|---|---|---|---|---|
| Issaquah / East King | 1,593 | Bloom start | Full bloom | 231 |
| Seattle / UW | 1,554 | Bloom start | Full bloom | 270 |
| Kent / Auburn | 1,537 | Bloom start | Full bloom | 287 |
| Olympia / Tumwater | 1,505 | Bloom start | Full bloom | 320 |
| Bellingham / Whatcom | 1,483 | Bloom start | Full bloom | 341 |
| Tacoma / Puyallup | 1,472 | Bloom start | Full bloom | 352 |
| Sequim / Rain Shadow | 1,434 | Bloom start | Full bloom | 390 |
| Stage | GDD32 | Typical Window |
|---|---|---|
| ● Bloom start BBCH 61 NOW | 1368 | Mar 15-May 15 |
| ○ Full bloom BBCH 65 NEXT | 1824 | — est. May 7 (forecast) |
| Bud break BBCH 07 | — | Feb 15-Mar 15 |
| Leaf emergence BBCH 11 | — | Mar 1-Apr 1 |
| Bloom end / petal fall BBCH 69 | — | Apr 15-May 31 |
| Fruit/seed development BBCH 71 | — | Jun 1-Aug 31 |
| Leaf drop BBCH 93 | — | Oct 15-Nov 30 |
| Dormancy BBCH 97 | — | Nov 15-Feb 28 |
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 Apr 23, 2026. Predicted dates use 16-day weather forecast through May 10, 2026, then climate normals.