Kousa Dogwood
Cornus kousa
Cornaceae · broadleaf deciduous tree · introduced
Last updated
Kousa dogwood (Cornus kousa, Cornaceae) is a moderate-growing deciduous tree from Japan, Korea, and China, reaching 15 to 25 feet in cultivation. It develops a vase-shaped form in youth that matures to distinctive horizontal branching. Four creamy-white, taper-pointed bracts (2.5 to 5 centimeters) surround small yellowish-green true flowers from May to June, blooming later than C. florida. Pink-red, spherical fruit (13 to 25 millimeters) hang on pendulous stalks. Fall color is scarlet.
Kousa dogwood grows in sun to part shade on well-drained soils (pH 5.5 to 6.5) with moderate water needs, hardy in Zones 5a to 8b. It is deer-resistant and more disease-resistant than flowering dogwood (C. florida), with documented resistance to anthracnose in several cultivars including 'Milky Way' and 'China Girl.' Disease associations still include anthracnose, powdery mildew, Armillaria root rot, and others. Pest associations include lecanium scale, oystershell scale, dogwood sawfly, and flea beetle. Cultivars include 'Wolf Eyes' (variegated), 'Gold Star' (gold-centered leaves), 'Scarlet Fire,' 'Radiant Rose,' and 'Sunsplash.'
Quick Facts
Phenological Calendar
As of April 3, 2026, Puget Sound stations range from 1070 to 1180.6 GDD₃₂. Kousa Dogwood typically reaches beginning of flowering at 2253 GDD₃₂, predicted around May 26.
Regional Season Tracker
GDD₃₂ accumulation across 7 Puget Sound stations · as of Apr 3, 2026| Station | GDD₃₂ | Current Stage | Next | To Go |
|---|---|---|---|---|
| Issaquah / East King | 1,181 | Pre-season | Beginning of flowering | 1,072 |
| Seattle / UW | 1,171 | Pre-season | Beginning of flowering | 1,082 |
| Kent / Auburn | 1,111 | Pre-season | Beginning of flowering | 1,142 |
| Olympia / Tumwater | 1,106 | Pre-season | Beginning of flowering | 1,147 |
| Bellingham / Whatcom | 1,101 | Pre-season | Beginning of flowering | 1,152 |
| Tacoma / Puyallup | 1,075 | Pre-season | Beginning of flowering | 1,178 |
| Sequim / Rain Shadow | 1,070 | Pre-season | Beginning of flowering | 1,183 |
| Stage | GDD32 | Typical Window |
|---|---|---|
| ○ Beginning of flowering BBCH 61 NEXT | 2253 | — est. May 26 (avg) |
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 Apr 3, 2026. Predicted dates use 16-day weather forecast through Apr 19, 2026, then climate normals.