Catawba Rhododendron
Rhododendron catawbiense
Ericaceae · broadleaf evergreen shrub · native
Last updated
Catawba rhododendron (Rhododendron catawbiense) is a broadleaf evergreen shrub in the Ericaceae family native to the Allegheny Mountains of the eastern United States. Named for the Catawba River in North Carolina, it reaches 6 ft tall and is notably cold-hardy to -25F. It blooms on previous season's wood.
Catawba rhododendron prefers part shade with acidic soil. It has a significant pest and disease burden with 35 diseases and 21 pests documented. One cultivar is available in the trade. All parts are poisonous to humans, cats, dogs, and horses.
Quick Facts
Phenological Calendar
As of April 3, 2026, Puget Sound stations range from 1070 to 1180.6 GDD₃₂. Catawba Rhododendron typically reaches 'first bloom' at 1325 GDD₃₂, predicted around Apr 14.
Regional Season Tracker
GDD₃₂ accumulation across 7 Puget Sound stations · as of Apr 3, 2026| Station | GDD₃₂ | Current Stage | Next | To Go |
|---|---|---|---|---|
| Issaquah / East King | 1,181 | Pre-season | 'First bloom' | 144 |
| Seattle / UW | 1,171 | Pre-season | 'First bloom' | 154 |
| Kent / Auburn | 1,111 | Pre-season | 'First bloom' | 214 |
| Olympia / Tumwater | 1,106 | Pre-season | 'First bloom' | 219 |
| Bellingham / Whatcom | 1,101 | Pre-season | 'First bloom' | 224 |
| Tacoma / Puyallup | 1,075 | Pre-season | 'First bloom' | 250 |
| Sequim / Rain Shadow | 1,070 | Pre-season | 'First bloom' | 255 |
| Stage | GDD32 | Typical Window |
|---|---|---|
| ○ 'First bloom' BBCH '61' NEXT | 1325 | '' est. Apr 14 (forecast) |
| 'Full bloom' BBCH '65' | 1580 | '' est. Apr 27 (avg) |
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 3, 2026. Predicted dates use 16-day weather forecast through Apr 19, 2026, then climate normals.