Douglas Maple
Acer glabrum var. douglasii
Sapindaceae, Aceraceae · broadleaf deciduous tree · native
Last updated
This profile synthesizes data from multiple published sources. Expert field review is in progress.
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 23, 2026, Puget Sound stations range from 1434.4 to 1592.7 GDD₃₂. Douglas Maple has passed 'leaf emergence' (1234 GDD₃₂).
Regional Season Tracker
GDD₃₂ accumulation across 7 Puget Sound stations · as of Apr 23, 2026| Station | GDD₃₂ | Current Stage | Next | To Go |
|---|---|---|---|---|
| Issaquah / East King | 1,593 | 'Leaf emergence' | — | — |
| Seattle / UW | 1,554 | 'Leaf emergence' | — | — |
| Kent / Auburn | 1,537 | 'Leaf emergence' | — | — |
| Olympia / Tumwater | 1,505 | 'Leaf emergence' | — | — |
| Bellingham / Whatcom | 1,483 | 'Leaf emergence' | — | — |
| Tacoma / Puyallup | 1,472 | 'Leaf emergence' | — | — |
| Sequim / Rain Shadow | 1,434 | 'Leaf emergence' | — | — |
| Stage | GDD32 | Typical Window |
|---|---|---|
| 'First bloom' BBCH '61' | 982 | '' |
| 'Flower buds visible' BBCH '51' | 982 | '' |
| 'Bud break' BBCH '07' | 1026 | '' |
| ● 'Leaf emergence' BBCH '11' NOW | 1234 | '' |
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 23, 2026. Predicted dates use 16-day weather forecast through May 10, 2026, then climate normals.