American Yellowwood
Cladrastis kentukea
Fabaceae · broadleaf deciduous tree · introduced
Last updated
American yellowwood (Cladrastis kentukea, Fabaceae) is a deciduous tree native to the southeastern United States (North Carolina, Tennessee, and surrounding states), where it occurs naturally on limestone cliffs and ridges. It reaches 30 to 50 feet tall with low branching and a broad, rounded crown of delicate branches. Odd-pinnately compound leaves (20 to 30 centimeters, 7 to 9 leaflets) turn yellow-orange in fall. Small, fragrant white flowers hang in pendulous clusters in May to June, followed by brown legume pods.
American yellowwood grows in sun to part shade on well-drained soils across a broad pH range (4.8 to 7.5) with low water needs and drought tolerance once established, hardy in Zones 4a to 8b. Growth is moderate, reaching about 25 feet at 20 years. No pest or disease issues are documented. No cultivars are in the trade. The tree provides nesting sites for songbirds and pollen and nectar for bees and pollinators.
Quick Facts
Phenological Calendar
As of April 19, 2026, Puget Sound stations range from 1342.9 to 1500.8 GDD₃₂. American Yellowwood typically reaches 'first bloom' at 2049 GDD₃₂, predicted around May 14.
Regional Season Tracker
GDD₃₂ accumulation across 7 Puget Sound stations · as of Apr 19, 2026| Station | GDD₃₂ | Current Stage | Next | To Go |
|---|---|---|---|---|
| Issaquah / East King | 1,501 | Pre-season | 'First bloom' | 548 |
| Seattle / UW | 1,465 | Pre-season | 'First bloom' | 584 |
| Kent / Auburn | 1,441 | Pre-season | 'First bloom' | 608 |
| Olympia / Tumwater | 1,415 | Pre-season | 'First bloom' | 634 |
| Bellingham / Whatcom | 1,390 | Pre-season | 'First bloom' | 659 |
| Tacoma / Puyallup | 1,381 | Pre-season | 'First bloom' | 669 |
| Sequim / Rain Shadow | 1,343 | Pre-season | 'First bloom' | 706 |
| Stage | GDD32 | Typical Window |
|---|---|---|
| ○ 'First bloom' BBCH '61' NEXT | 2049 | '' est. May 14 (avg) |
| 'Full bloom' BBCH '65' | 2336 | '' est. May 26 (avg) |
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 19, 2026. Predicted dates use 16-day weather forecast through May 5, 2026, then climate normals.