Japanese Snowbell
'Full bloom'Styrax japonicus
Styracaceae · broadleaf deciduous tree · introduced
Last updated
Japanese snowbell is a deciduous tree native to Japan, reaching 20-30 feet tall with a pyramidal form and smooth gray bark. The tree produces white, slightly fragrant bell-shaped flowers hanging from branch undersides in early summer and opposite, ovate leaves with fine fall color.
Japanese snowbell thrives in partial shade to full sun with well-drained, slightly acidic to neutral soil and moderate moisture. Hardy to zones 5-8, it is slow to medium in growth. The distinctive downward-facing flowers are a major ornamental asset, and the plant is excellent for specimen plantings. It requires consistent moisture and does not tolerate drought.
Plant Profile
Size & Form
Site Requirements
Ornamental Interest
Field Observations
Phenological Calendar
As of June 4, 2026, Puget Sound stations range from 2458.5 to 2700.8 GDD₃₂. Japanese Snowbell has passed 'full bloom' (2336 GDD₃₂).
Regional Season Tracker
GDD₃₂ accumulation across 7 Puget Sound stations · as of Jun 4, 2026| Station | GDD₃₂ | Current Stage | Next | To Go |
|---|---|---|---|---|
| Issaquah / East King | 2,701 | 'Full bloom' | — | — |
| Kent / Auburn | 2,695 | 'Full bloom' | — | — |
| Seattle / UW | 2,637 | 'Full bloom' | — | — |
| Olympia / Tumwater | 2,598 | 'Full bloom' | — | — |
| Tacoma / Puyallup | 2,564 | 'Full bloom' | — | — |
| Bellingham / Whatcom | 2,560 | 'Full bloom' | — | — |
| Sequim / Rain Shadow | 2,459 | 'Full bloom' | — | — |
View full calendar (4 stages)
| Stage | GDD32 | Typical Window |
|---|---|---|
| 'Leaf emergence' BBCH '11' | — Observed | 'Early April' |
| 'Flower buds visible' BBCH '51' | — Observed | 'Early-mid May' |
| 'First bloom' BBCH '61' | 1932 | '' |
| ● 'Full bloom' BBCH '65' NOW | 2336 | 'Late May-early Jun' |
Source: 'Master catalog (UMD), converted GDD50->GDD32 via Kent bloom-date mapping + field observations' About GDD₃₂ →
Season tracker for Kent / Auburn as of Jun 4, 2026. Predicted dates use 16-day weather forecast through Jun 20, 2026, then climate normals.