Douglas Maple
Acer glabrum var. douglasii
Sapindaceae, Aceraceae · broadleaf deciduous tree · native
Last updated
A variety of Rocky Mountain maple native from southeastern Alaska through British Columbia, Alberta, Montana, Idaho, Washington, and Oregon. Typically a compact shrub or small tree to 30 feet with 3 to 5-lobed leaves, 6 to 20 cm across, shiny dark green above and blue-green below on reddish-tinged petioles. Distinguished from other varieties by shallow leaf sinuses and red twigs. Named for David Douglas, the Scottish botanist. Flowers are yellowish-green, 5 mm, in terminal clusters. Samaras are 2 to 2.5 cm, green turning pink or reddish, then light brown. Fall color spans brown, crimson, orange, and yellow.
Hardy to Zone 4a. Full sun to part shade. Easy to grow under a wide range of conditions: exposed or sheltered, wet or dry soils. Twenty diseases and fifteen pests documented. No cultivars in the trade. Multi-stemmed habit and modest size suit naturalized and restoration plantings.
Quick Facts
Phenological Calendar
As of April 3, 2026, Puget Sound stations range from 1070 to 1180.6 GDD₃₂. Douglas Maple has reached 'bud break' (1026 GDD₃₂) and is approaching 'leaf emergence', predicted around Apr 9.
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 | 'Bud break' | 'Leaf emergence' | 53 |
| Seattle / UW | 1,171 | 'Bud break' | 'Leaf emergence' | 63 |
| Kent / Auburn | 1,111 | 'Bud break' | 'Leaf emergence' | 123 |
| Olympia / Tumwater | 1,106 | 'Bud break' | 'Leaf emergence' | 128 |
| Bellingham / Whatcom | 1,101 | 'Bud break' | 'Leaf emergence' | 133 |
| Tacoma / Puyallup | 1,075 | 'Bud break' | 'Leaf emergence' | 159 |
| Sequim / Rain Shadow | 1,070 | 'Bud break' | 'Leaf emergence' | 164 |
| Stage | GDD32 | Typical Window |
|---|---|---|
| 'First bloom' BBCH '61' | 982 | '' |
| 'Flower buds visible' BBCH '51' | 982 | '' |
| ● 'Bud break' BBCH '07' NOW | 1026 | '' |
| ○ 'Leaf emergence' BBCH '11' NEXT | 1234 | '' est. Apr 9 (forecast) |
GDD = Growing Degree Days (base 32°F, Jan 1 start). Why base 32? GDD₃₂ thresholds from USA National Phenology Network citizen science observations (WA+OR). Season tracker for Kent / Auburn as of Apr 3, 2026. Predicted dates use 16-day weather forecast through Apr 19, 2026, then climate normals.