Japanese Pieris
'Full bloom'Pieris japonica
Ericaceae · broadleaf evergreen shrub · introduced
Last updated
Pieris japonica (Ericaceae) is a broadleaf evergreen shrub native to Japan. It grows to about 12 feet tall with a dense, layered habit. Drooping chains of small, urn-shaped, fragrant white to pink flowers appear in early spring from buds formed the previous fall. New growth emerges in shades of red, bronze, or copper before maturing to glossy dark green.
Japanese pieris requires acidic, moist, well-drained soil in part shade. It is susceptible to lace bug, which causes stippled, bleached foliage, and to Phytophthora root rot in poorly drained sites. Many cultivars are available offering variations in flower color (white to deep pink), new growth color, and mature size. It blooms on old wood and should be pruned after flowering. All parts are toxic (andromedotoxin). Hardy in Zones 7a to 8b.
Quick Facts
First Generation Nymph Emergence
Spring Egg Laying
Adult Emergence & Foliar Feeding
Field Observations
Phenological Calendar
As of May 13, 2026, Puget Sound stations range from 1906.2 to 2098.2 GDD₃₂. Japanese Pieris has passed 'full bloom' (798 GDD₃₂).
Regional Season Tracker
GDD₃₂ accumulation across 7 Puget Sound stations · as of May 13, 2026| Station | GDD₃₂ | Current Stage | Next | To Go |
|---|---|---|---|---|
| Issaquah / East King | 2,098 | 'Full bloom' | — | — |
| Kent / Auburn | 2,089 | 'Full bloom' | — | — |
| Seattle / UW | 2,063 | 'Full bloom' | — | — |
| Olympia / Tumwater | 2,025 | 'Full bloom' | — | — |
| Tacoma / Puyallup | 1,993 | 'Full bloom' | — | — |
| Bellingham / Whatcom | 1,972 | 'Full bloom' | — | — |
| Sequim / Rain Shadow | 1,906 | 'Full bloom' | — | — |
| Stage | GDD32 | Typical Window |
|---|---|---|
| 'First bloom' BBCH '61' | 580 | '' |
| ● 'Full bloom' BBCH '65' NOW | 798 | '' |
| 'Late bloom / mature flowers' BBCH '67' | — | '' |
| Leaf emergence BBCH 11 | — | — |
| Leaf expansion BBCH 12 | — | — |
Sources: 'Master catalog (OSU), converted GDD50->GDD32 via Kent bloom-date mapping' ; 'Field observation, Issaquah, WA' About GDD₃₂ →
Season tracker for Kent / Auburn as of May 13, 2026. Predicted dates use 16-day weather forecast through May 29, 2026, then climate normals.