Rhubarb
Rheum rhabarbarum
· perennial · introduced
Last updated
Data Maturity Baseline
This profile contains verified botanical data. Regional field notes and expert review are in progress.
Phenological Calendar
As of April 23, 2026, Puget Sound stations range from 1434.4 to 1592.7 GDD₃₂. Rhubarb has passed 'flower buds visible' (1428 GDD₃₂).
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 | 'Flower buds visible' | — | — |
| Seattle / UW | 1,554 | 'Flower buds visible' | — | — |
| Kent / Auburn | 1,537 | 'Flower buds visible' | — | — |
| Olympia / Tumwater | 1,505 | 'Flower buds visible' | — | — |
| Bellingham / Whatcom | 1,483 | 'Flower buds visible' | — | — |
| Tacoma / Puyallup | 1,472 | 'Flower buds visible' | — | — |
| Sequim / Rain Shadow | 1,434 | 'Flower buds visible' | — | — |
| Stage | GDD32 | Typical Window |
|---|---|---|
| ● 'Flower buds visible' BBCH '51' NOW | 1428 | '' |
GDD = Growing Degree Days (base 32°F, Jan 1 start). Why base 32? GDD₃₂ thresholds from USA National Phenology Network citizen science observations (WA+OR). Season tracker for Kent / Auburn as of Apr 23, 2026. Predicted dates use 16-day weather forecast through May 10, 2026, then climate normals.
Diseases (4)
Gray Mold Symptom category — not a single disease Leaf Spot Blueberry leaf mottle virus or Abiotic Red Leaf Raspberry bushy dwarf virus and related viruses Virus