Bearberry Cotoneaster
Full bloomCotoneaster dammeri
Rosaceae · vine groundcover · introduced
Last updated
Bearberry cotoneaster (Cotoneaster dammeri, Rosaceae) is an evergreen to semi-evergreen prostrate groundcover from central China, typically reaching about 2 feet tall. It roots readily along the ground, forming dense, creeping mats. Small white flowers with pink outer sides appear in May, followed by bright red, glossy berries (6 millimeters) that persist into fall. Foliage turns reddish-bronze to purple in winter.
Bearberry cotoneaster grows in full sun to part shade on adaptable, well-drained soils, hardy in Zones 5a to 8b. It is easy to grow and useful for erosion control on banks and slopes. Documented diseases include scab, bacterial blight, fire blight, and Phytophthora root rot. Pest associations include spider mite, cotoneaster webworm, and aphid. Cultivars include 'Lowfast' (mat-forming, 10 to 15 inches), 'Eichholz' (dwarf mounding, 1 foot), and 'Coral Beauty' (pink-coral fruit, 2 feet).
Plant Profile
Size & Form
Site Requirements
Ornamental Interest
Field Observations
Bloom Infection Window
Peak Population & Dispersal
Growing Season Stress Expression
Diseases: Regionally Documented (4)
Pests: Regionally Documented (3)
Phenological Calendar
As of June 3, 2026, Puget Sound stations range from 2435.5 to 2672.8 GDD₃₂. Bearberry Cotoneaster has passed full bloom (2144 GDD₃₂).
Regional Season Tracker
GDD₃₂ accumulation across 7 Puget Sound stations · as of Jun 3, 2026| Station | GDD₃₂ | Current Stage | Next | To Go |
|---|---|---|---|---|
| Issaquah / East King | 2,673 | Full bloom | — | — |
| Kent / Auburn | 2,665 | Full bloom | — | — |
| Seattle / UW | 2,610 | Full bloom | — | — |
| Olympia / Tumwater | 2,570 | Full bloom | — | — |
| Tacoma / Puyallup | 2,535 | Full bloom | — | — |
| Bellingham / Whatcom | 2,533 | Full bloom | — | — |
| Sequim / Rain Shadow | 2,436 | Full bloom | — | — |
View full calendar (1 stages)
| Stage | GDD32 | Typical Window |
|---|---|---|
| ● Full bloom BBCH 65 NOW | 2144 Observed | mid-May |
Source: Field observation, Lake Wilderness Arboretum (Maple Valley, WA), 2026-05-15. GDD₃₂ estimated from Issaquah May 14: 2121.1 + ~23/day trend. About GDD₃₂ →
Season tracker for Kent / Auburn as of Jun 3, 2026. Predicted dates use 16-day weather forecast through Jun 19, 2026, then climate normals.