Carolina Silverbell Mountain Silverbell
Halesia carolina
Styracacaceae · broadleaf deciduous tree · introduced
Last updated
Quick Facts
Height
30–40 ft
Spread
32 ft
Growth Rate
Moderate
Light
Part Shade
Soil
Wet Tolerant
Water
Moderate
Hardiness
Zones 4a–8b
Bloom Time
April
Fall Color
Yellow
Origin
the Appalachians Mountains of North Carolina to Tennessee
Phenological Calendar
As of May 24, 2026, Puget Sound stations range from 2172.5 to 2394 GDD₃₂. Carolina Silverbell Mountain Silverbell has passed full bloom (1197 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 (9 stages)
| Stage | GDD32 | Typical Window |
|---|---|---|
| Bloom start BBCH 61 | 959 | Apr 1-Apr 30 |
| ● Full bloom BBCH 65 NOW | 1197 | — |
| Bud break BBCH 07 | — | Feb 15-Mar 15 |
| Leaf emergence BBCH 11 | — | Mar 1-Apr 1 |
| Bloom end / petal fall BBCH 69 | — | Apr 15-May 15 |
| Fruit/seed development BBCH 71 | — | Jun 1-Aug 31 |
| Fruit/seed maturity BBCH 85 | — | Sep 1-Nov 30 |
| Fall color / leaf senescence BBCH 93 | — | Oct 1-Nov 15 |
| Dormancy BBCH 97 | — | Nov 15-Feb 28 |
Range: 635–790 GDD₃₂
(6yr)
Sources: USDA Plants Database (seasonal estimate) ; OSU phenology catalog (OSU: weather.cfaes.osu.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.
Data Maturity Baseline Extension data. Expert review underway.