Catawba Rhododendron
'Full bloom'Rhododendron catawbiense
Ericaceae · broadleaf evergreen shrub · native
Last updated
A broadleaf evergreen shrub reaching 6 ft tall and 8 to 10 ft wide, native to the Allegheny Mountains of the eastern United States. Named after the Catawba River in North Carolina. One of the most cold-hardy elepidote species, tolerating temperatures to -25F. Leaves are medium-sized, oval to oblong, smooth and shiny dark green above, cupped in shape.
Part shade on acidic, well-drained to adaptable soil. Low to moderate water needs. One of the most important parent species in rhododendron hybridizing, contributing extreme cold hardiness and dense habit to countless cultivars. Twenty-one diseases and 15 pests documented at the genus level.
Quick Facts
Root Colonization (Spring–Fall)
Infection at Bud Break
Apothecia Formation & Spore Release
Aecial Stage (Alternate Host)
+ 13 more — see full disease and pest lists below
Phenological Calendar
As of May 13, 2026, Puget Sound stations range from 1906.2 to 2098.2 GDD₃₂. Catawba Rhododendron has passed 'full bloom' (1580 GDD₃₂).
Regional Season Tracker
GDD₃₂ accumulation across 7 Puget Sound stations · as of May 13, 2026| Station | GDD₃₂ | Current Stage | Next | To Go |
|---|---|---|---|---|
| Issaquah / East King | 2,098 | 'Full bloom' | — | — |
| Kent / Auburn | 2,089 | 'Full bloom' | — | — |
| Seattle / UW | 2,063 | 'Full bloom' | — | — |
| Olympia / Tumwater | 2,025 | 'Full bloom' | — | — |
| Tacoma / Puyallup | 1,993 | 'Full bloom' | — | — |
| Bellingham / Whatcom | 1,972 | 'Full bloom' | — | — |
| Sequim / Rain Shadow | 1,906 | 'Full bloom' | — | — |
| Stage | GDD32 | Typical Window |
|---|---|---|
| 'First bloom' BBCH '61' | 1325 | '' |
| ● 'Full bloom' BBCH '65' NOW | 1580 | '' |
Source: 'Master catalog (OSU), converted GDD50->GDD32 via Kent bloom-date mapping' About GDD₃₂ →
Season tracker for Kent / Auburn as of May 13, 2026. Predicted dates use 16-day weather forecast through May 29, 2026, then climate normals.