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
As of April 19, 2026, Puget Sound stations range from 1342.9 to 1500.8 GDD₃₂. Compact Garland Spirea has passed beginning of flowering (1391 GDD₃₂).
Regional Season Tracker
GDD₃₂ accumulation across 7 Puget Sound stations · as of Apr 19, 2026| Station | GDD₃₂ | Current Stage | Next | To Go |
|---|---|---|---|---|
| Issaquah / East King | 1,501 | Beginning of flowering | — | — |
| Seattle / UW | 1,465 | Beginning of flowering | — | — |
| Kent / Auburn | 1,441 | Beginning of flowering | — | — |
| Olympia / Tumwater | 1,415 | Beginning of flowering | — | — |
| Bellingham / Whatcom | 1,390 | Full bloom | Beginning of flowering | 1 |
| Tacoma / Puyallup | 1,381 | Full bloom | Beginning of flowering | 11 |
| Sequim / Rain Shadow | 1,343 | Pre-season | Full bloom | 34 |
| Stage | GDD32 | Typical Window |
|---|---|---|
| Full bloom BBCH 65 | 1377 | — |
| ● Beginning of flowering BBCH 61 NOW | 1391 | — |
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 Apr 19, 2026. Predicted dates use 16-day weather forecast through May 5, 2026, then climate normals.