Mountain pieris
Pieris floribunda
Ericaceae · [VERIFY] · native
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
Regional Season Tracker
GDD₃₂ accumulation across 7 Puget Sound stations · as of Mar 30, 2026| Station | GDD₃₂ | Current Stage | Next | To Go |
|---|---|---|---|---|
| Issaquah / East King | 1,116 | Pre-season | Full bloom | 27 |
| Seattle / UW | 1,112 | Pre-season | Full bloom | 31 |
| Olympia / Tumwater | 1,049 | Pre-season | Full bloom | 95 |
| Kent / Auburn | 1,048 | Pre-season | Full bloom | 95 |
| Bellingham / Whatcom | 1,041 | Pre-season | Full bloom | 102 |
| Tacoma / Puyallup | 1,017 | Pre-season | Full bloom | 126 |
| Sequim / Rain Shadow | 1,012 | Pre-season | Full bloom | 131 |
| Stage | GDD32 | Typical Window |
|---|---|---|
| ○ Full bloom BBCH 65 NEXT | 1143 | — est. Apr 5 (forecast) |
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 Mar 30, 2026. Predicted dates use 16-day weather forecast through Apr 15, 2026, then climate normals.