American Yellowwood

Cladrastis kentukea

Fabaceae · broadleaf deciduous tree · introduced

Last updated

Data Coverage 3 of 6 dimensions
Site Data
Threats
Cultivars
Phenology
GDD Thresholds
Puget Sound

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

Height
30–50 ft
Growth Rate
Moderate
Light
Sun to Part Shade
Soil
Well Drained
Water
Low
Hardiness
Zone Zones 4a–8b
Bloom Time
May
Fall Color
Brown
Origin
limestone cliffs and ridges

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)
Range: 1621–1894 GDD₃₂ (6yr)

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.