Northern Catalpa
Catalpa speciosa
Bignoniaceae · broadleaf deciduous tree · introduced
Last updated
Plant Profile
Size & Form
Height
40–60 ft
Spread
8-16 ft
Growth Rate
Fast
Size at 20 yr
20 ft
Lifespan
Long-lived
Site Requirements
Light
Full Sun
Soil Drainage
Well Drained
Soil pH
5.5-7.0
Water
Low
Drought Tolerance
Medium
Hardiness
Zones 4a–8b
Ornamental Interest
Bloom Time
May to June
Fall Color
Yellow, insignificant
Origin
Illinois and Indiana to western Tennessee and northern
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. Northern Catalpa has reached 'first bloom' (2336 GDD₃₂) and is approaching 'full bloom', predicted around Jun 6.
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 | 'First bloom' | 'Full bloom' | 62 |
| Kent / Auburn | 2,665 | 'First bloom' | 'Full bloom' | 70 |
| Seattle / UW | 2,610 | 'First bloom' | 'Full bloom' | 125 |
| Olympia / Tumwater | 2,570 | 'First bloom' | 'Full bloom' | 166 |
| Tacoma / Puyallup | 2,535 | 'First bloom' | 'Full bloom' | 200 |
| Bellingham / Whatcom | 2,533 | 'First bloom' | 'Full bloom' | 202 |
| Sequim / Rain Shadow | 2,436 | 'First bloom' | 'Full bloom' | 300 |
View full calendar (2 stages)
| Stage | GDD32 | Typical Window |
|---|---|---|
| ● 'First bloom' BBCH '61' NOW | 2336 | '' |
| ○ 'Full bloom' BBCH '65' NEXT | 2735 | '' est. Jun 6 (forecast) |
Range: 1890–2189 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.