Southern Catalpa
Catalpa bignonioides
Bignoniaceae · broadleaf deciduous tree · introduced
Last updated
Plant Profile
Size & Form
Height
30–40 ft
Spread
20-40 ft
Growth Rate
Fast
Size at 20 yr
66 ft
Lifespan
Long-lived
Site Requirements
Light
Sun to Part Shade
Soil Drainage
Well Drained
Soil pH
5.5-7.5
Water
Low
Drought Tolerance
Medium
Hardiness
Zones 5a–8b
Ornamental Interest
Bloom Time
May to June
Fall Color
Yes
Origin
Georgia, Florida, Alabama, and Mississippi
Watch for this season
Root Colonization Period
Diseases: Regionally Documented (1)
Phenological Calendar
As of June 3, 2026, Puget Sound stations range from 2435.5 to 2672.8 GDD₃₂. Southern Catalpa typically reaches 'first bloom' at 2878 GDD₃₂, predicted around Jun 12.
Regional Season Tracker
GDD₃₂ accumulation across 7 Puget Sound stations · as of Jun 3, 2026| Station | GDD₃₂ | Current Stage | Next | To Go |
|---|---|---|---|---|
| Issaquah / East King | 2,673 | Pre-season | 'First bloom' | 205 |
| Kent / Auburn | 2,665 | Pre-season | 'First bloom' | 213 |
| Seattle / UW | 2,610 | Pre-season | 'First bloom' | 268 |
| Olympia / Tumwater | 2,570 | Pre-season | 'First bloom' | 309 |
| Tacoma / Puyallup | 2,535 | Pre-season | 'First bloom' | 343 |
| Bellingham / Whatcom | 2,533 | Pre-season | 'First bloom' | 345 |
| Sequim / Rain Shadow | 2,436 | Pre-season | 'First bloom' | 443 |
View full calendar (2 stages)
| Stage | GDD32 | Typical Window |
|---|---|---|
| ○ 'First bloom' BBCH '61' NEXT | 2878 | '' est. Jun 12 (forecast) |
| 'Full bloom' BBCH '65' | 3248 | '' est. Jun 25 (avg) |
Range: 2365–2748 GDD₃₂
(6yr)
Source: 'Master catalog (OSU), converted GDD50->GDD32 via Kent bloom-date mapping' About GDD₃₂ →
Season tracker for Kent / Auburn as of Jun 3, 2026. Predicted dates use 16-day weather forecast through Jun 19, 2026, then climate normals.
Data Maturity Baseline Extension data. Expert review underway.