Southern Catalpa
Catalpa bignonioides
Bignoniaceae · broadleaf deciduous tree · native
Last updated
Data Maturity Baseline
This profile contains verified botanical data. Regional field notes and expert review are in progress.
Quick Facts
Height
30–40 ft
Growth Rate
Fast
Light
Sun to Part Shade
Soil
Well Drained
Water
Low
Hardiness
Zone Zones 5a–8b
Bloom Time
May to June
Origin
Georgia, Florida, Alabama, and Mississippi
Phenological Calendar
As of April 23, 2026, Puget Sound stations range from 1434.4 to 1592.7 GDD₃₂. Southern Catalpa typically reaches 'first bloom' at 2878 GDD₃₂, predicted around Jun 18.
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 | Pre-season | 'First bloom' | 1,285 |
| Seattle / UW | 1,554 | Pre-season | 'First bloom' | 1,324 |
| Kent / Auburn | 1,537 | Pre-season | 'First bloom' | 1,341 |
| Olympia / Tumwater | 1,505 | Pre-season | 'First bloom' | 1,374 |
| Bellingham / Whatcom | 1,483 | Pre-season | 'First bloom' | 1,395 |
| Tacoma / Puyallup | 1,472 | Pre-season | 'First bloom' | 1,406 |
| Sequim / Rain Shadow | 1,434 | Pre-season | 'First bloom' | 1,444 |
| Stage | GDD32 | Typical Window |
|---|---|---|
| ○ 'First bloom' BBCH '61' NEXT | 2878 | '' est. Jun 18 (avg) |
| 'Full bloom' BBCH '65' | 3248 | '' est. Jul 1 (avg) |
Range: 2365–2748 GDD₃₂
(6yr)
GDD = Growing Degree Days (base 32°F, Jan 1 start). Why base 32? Hover over GDD values for source details. Season tracker for Kent / Auburn as of Apr 23, 2026. Predicted dates use 16-day weather forecast through May 10, 2026, then climate normals.