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
Phenological Calendar
As of April 3, 2026, Puget Sound stations range from 1070 to 1180.6 GDD₃₂. Thimbleberry Western Thimbleberry has reached 'bud break' (817 GDD₃₂) and is approaching 'leaf emergence', predicted around Apr 13.
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 | 'Bud break' | 'Leaf emergence' | 124 |
| Seattle / UW | 1,171 | 'Bud break' | 'Leaf emergence' | 134 |
| Kent / Auburn | 1,111 | 'Bud break' | 'Leaf emergence' | 194 |
| Olympia / Tumwater | 1,106 | 'Bud break' | 'Leaf emergence' | 199 |
| Bellingham / Whatcom | 1,101 | 'Bud break' | 'Leaf emergence' | 204 |
| Tacoma / Puyallup | 1,075 | 'Bud break' | 'Leaf emergence' | 230 |
| Sequim / Rain Shadow | 1,070 | 'Bud break' | 'Leaf emergence' | 235 |
| Stage | GDD32 | Typical Window |
|---|---|---|
| ● 'Bud break' BBCH '07' NOW | 817 | '' |
| ○ 'Leaf emergence' BBCH '11' NEXT | 1305 | '' est. Apr 13 (forecast) |
| 'Flower buds visible' BBCH '51' | 1490 | '' est. Apr 22 (avg) |
| 'First bloom' BBCH '61' | 1855 | '' est. May 9 (avg) |
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 3, 2026. Predicted dates use 16-day weather forecast through Apr 19, 2026, then climate normals.