Mountain pieris
Pieris floribunda
Ericaceae · [VERIFY] · introduced
Last updated
Pieris floribunda (Ericaceae) is a broadleaf evergreen shrub native to the Appalachian Mountains of the southeastern United States. It grows 4 to 6 feet tall with a rounded, dense habit. Upright panicles of small, white, urn-shaped flowers appear in early spring. Unlike P. japonica, the flower clusters are held upright rather than pendulous.
Mountain pieris requires acidic, moist, well-drained soil in part shade. It is hardier and more resistant to lace bug than P. japonica. Growth is slow. No significant disease problems are documented beyond those common to ericaceous plants. Hardy in Zones 4 to 6.
Quick Facts
Phenological Calendar
As of May 24, 2026, Puget Sound stations range from 2172.5 to 2394 GDD₃₂. Mountain pieris has passed full bloom (1143 GDD₃₂).
Regional Season Tracker
GDD₃₂ accumulation across 7 Puget Sound stations · as of May 24, 2026| Station | GDD₃₂ | Current Stage | Next | To Go |
|---|---|---|---|---|
| Issaquah / East King | 2,394 | Full bloom | — | — |
| Kent / Auburn | 2,373 | Full bloom | — | — |
| Seattle / UW | 2,332 | Full bloom | — | — |
| Olympia / Tumwater | 2,295 | Full bloom | — | — |
| Tacoma / Puyallup | 2,259 | Full bloom | — | — |
| Bellingham / Whatcom | 2,256 | Full bloom | — | — |
| Sequim / Rain Shadow | 2,173 | Full bloom | — | — |
View full calendar (1 stages)
| Stage | GDD32 | Typical Window |
|---|---|---|
| ● Full bloom BBCH 65 NOW | 1143 | — |
Source: UMD phenology catalog (UMD: extension.umd.edu) About GDD₃₂ →
Season tracker for Kent / Auburn as of May 24, 2026. Predicted dates use 16-day weather forecast through Jun 9, 2026, then climate normals.