Snowbrush
Ceanothus velutinus
Rhamnaceae · broadleaf evergreen shrub · native
Last updated
This profile synthesizes data from multiple published sources. Expert field review is in progress.
Snowbrush (Ceanothus velutinus, Rhamnaceae) is a native broadleaf shrub ranging from British Columbia and Saskatchewan through much of the western United States. It reaches 2 to 10 feet tall with sticky, aromatic leaves that emit a distinctive sweet odor when crushed in warm weather. Small white flowers appear in dense clusters (panicles) 5 to 13 centimeters long. Two varieties are recognized: var. hookeri and var. velutinus.
Snowbrush grows in full sun to part shade and is a nitrogen-fixing species with root nodules, important in post-disturbance succession. Thickets are not long-lived, typically declining after about 15 years. Documented diseases include leaf spot and root rot; pest associations include ceanothus leafminer, root weevil, and whitefly. No cultivars are in the trade. Bloom occurs on the current season's growth; prune in late winter to early spring.
Quick Facts
Phenological Calendar
As of April 24, 2026, Puget Sound stations range from 1455.1 to 1613.4 GDD₃₂. Snowbrush typically reaches bloom start at 1775 GDD₃₂, predicted around May 4.
Regional Season Tracker
GDD₃₂ accumulation across 7 Puget Sound stations · as of Apr 24, 2026| Station | GDD₃₂ | Current Stage | Next | To Go |
|---|---|---|---|---|
| Issaquah / East King | 1,613 | Pre-season | Bloom start | 162 |
| Seattle / UW | 1,574 | Pre-season | Bloom start | 201 |
| Kent / Auburn | 1,559 | Pre-season | Bloom start | 216 |
| Olympia / Tumwater | 1,524 | Pre-season | Bloom start | 252 |
| Bellingham / Whatcom | 1,504 | Pre-season | Bloom start | 271 |
| Tacoma / Puyallup | 1,492 | Pre-season | Bloom start | 283 |
| Sequim / Rain Shadow | 1,455 | Pre-season | Bloom start | 320 |
| Stage | GDD32 | Typical Window |
|---|---|---|
| ○ Bloom start BBCH 61 NEXT | 1775 | — est. May 4 (forecast) |
| Inflorescence emergence BBCH 51 | 3005 | — est. Jun 21 (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 24, 2026. Predicted dates use 16-day weather forecast through May 10, 2026, then climate normals.