Thimbleberry Western Thimbleberry
Rubus parviflorus
Rosaceae · broadleaf deciduous shrub · native
Last updated
Thimbleberry (Rubus parviflorus), also called western thimbleberry, is a broadleaf deciduous shrub in the Rosaceae family native to western North America. It reaches 3-8 ft tall with a 6 ft spread and forms thickets via rhizomatous spread. White (rarely pinkish) crinkled flowers 3-5 cm across appear in loose corymbs. It occurs in woodlands and canyons.
Thimbleberry is hardy in zones 3a-8b and tolerates full sun to shade with moist soil (pH 4.5-8.5) and moderate water with medium maintenance. Thirty-one diseases are documented with no pest records. The fruit has a moderate edibility rating (3/5) and moderate culinary and medicinal value.
Quick Facts
Primary Spore Release
Spring New Growth - Early Infection Window
Root Colonization Period
Active Below-ground Growth
+ 2 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. Thimbleberry Western Thimbleberry has passed 'first bloom' (1855 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 | 'First bloom' | — | — |
| Kent / Auburn | 2,089 | 'First bloom' | — | — |
| Seattle / UW | 2,063 | 'First bloom' | — | — |
| Olympia / Tumwater | 2,025 | 'First bloom' | — | — |
| Tacoma / Puyallup | 1,993 | 'First bloom' | — | — |
| Bellingham / Whatcom | 1,972 | 'First bloom' | — | — |
| Sequim / Rain Shadow | 1,906 | 'First bloom' | — | — |
| Stage | GDD32 | Typical Window |
|---|---|---|
| 'Bud break' BBCH '07' | 817 | '' |
| 'Leaf emergence' BBCH '11' | 1305 | '' |
| 'Flower buds visible' BBCH '51' | 1490 | '' |
| ● 'First bloom' BBCH '61' NOW | 1855 | '' |
Source: 'NPN citizen science observations (WA+OR), n=15, median. services.usanpn.org' 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.