Slender Deutzia
Deutzia gracilis
Saxifragaceae · broadleaf deciduous shrub · introduced
Last updated
Slender deutzia (Deutzia gracilis, Saxifragaceae) is a compact deciduous shrub from Japan, reaching 2 to 4 feet tall. Small white five-petaled flowers (13 to 19 millimeters) cover the plant in April to May. Opposite, oblong-lanceolate leaves (2.5 to 7.5 centimeters) on slender arching branches create a graceful form.
Slender deutzia grows in sun to part shade on adaptable, well-drained soils with moderate water needs, tolerating clay, hardy in Zones 4a to 8b. It blooms on old wood; prune immediately after flowering. No significant pest or disease issues are documented. Cultivars include 'Nikko' (2 feet, dense mounding, burgundy fall color) and 'Chardonnay Pearls' (3 feet, chartreuse-yellow foliage).
Quick Facts
Phenological Calendar
As of April 19, 2026, Puget Sound stations range from 1342.9 to 1500.8 GDD₃₂. Slender Deutzia has passed 'first bloom' (1229 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 | 'First bloom' | — | — |
| Seattle / UW | 1,465 | 'First bloom' | — | — |
| Kent / Auburn | 1,441 | 'First bloom' | — | — |
| Olympia / Tumwater | 1,415 | 'First bloom' | — | — |
| Bellingham / Whatcom | 1,390 | 'First bloom' | — | — |
| Tacoma / Puyallup | 1,381 | 'First bloom' | — | — |
| Sequim / Rain Shadow | 1,343 | 'First bloom' | — | — |
| Stage | GDD32 | Typical Window |
|---|---|---|
| ● 'First bloom' BBCH '61' NOW | 1229 | '' |
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.