Compact Garland Spirea
Spiraea x arguta
Rosaceae · [VERIFY] · introduced
Last updated
Compact garland spirea is a hybrid deciduous shrub reaching 2-3 feet tall and wide, producing small, narrow leaves and abundant clusters of white flowers arranged along arching branches in spring. The plant has a fine-textured, spreading habit.
This hybrid is hardy to zones 4-9 and thrives in full sun to light shade with well-drained soil. It is fast-growing and responds well to pruning. The plant is valued for its early spring bloom and fine texture in borders and naturalized gardens.
Quick Facts
Phenological Calendar
Regional Season Tracker
GDD₃₂ accumulation across 7 Puget Sound stations · as of Mar 30, 2026| Station | GDD₃₂ | Current Stage | Next | To Go |
|---|---|---|---|---|
| Issaquah / East King | 1,116 | Pre-season | Full bloom | 261 |
| Seattle / UW | 1,112 | Pre-season | Full bloom | 265 |
| Olympia / Tumwater | 1,049 | Pre-season | Full bloom | 329 |
| Kent / Auburn | 1,048 | Pre-season | Full bloom | 329 |
| Bellingham / Whatcom | 1,041 | Pre-season | Full bloom | 336 |
| Tacoma / Puyallup | 1,017 | Pre-season | Full bloom | 360 |
| Sequim / Rain Shadow | 1,012 | Pre-season | Full bloom | 365 |
| Stage | GDD32 | Typical Window |
|---|---|---|
| ○ Beginning of flowering BBCH 61 NEXT | 1391 | — est. Apr 16 (avg) |
| Full bloom BBCH 65 | 1377 | — est. Apr 15 (forecast) |
GDD = Growing Degree Days (base 32°F, Jan 1 start). Why base 32? Source GDD₅₀ thresholds from Herms 2004 (OSU, Secrest Arboretum, Ohio) and UMD IPMnet (Gill & Klick, mid-Atlantic), converted to GDD₃₂ via Kent bloom-date mapping. Season tracker for Kent / Auburn as of Mar 30, 2026. Predicted dates use 16-day weather forecast through Apr 15, 2026, then climate normals.