Douglas Maple
'Leaf emergence'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
Primary Spore Release
Spring Spore Germination and Infection
Spore Release (Fall & Spring Rains)
Primary Spore Release
+ 10 more — see full disease and pest lists below
Phenological Calendar
As of May 14, 2026, Puget Sound stations range from 1926.1 to 2121.1 GDD₃₂. Douglas Maple has passed 'leaf emergence' (1234 GDD₃₂).
Regional Season Tracker
GDD₃₂ accumulation across 7 Puget Sound stations · as of May 14, 2026| Station | GDD₃₂ | Current Stage | Next | To Go |
|---|---|---|---|---|
| Issaquah / East King | 2,121 | 'Leaf emergence' | — | — |
| Kent / Auburn | 2,113 | 'Leaf emergence' | — | — |
| Seattle / UW | 2,085 | 'Leaf emergence' | — | — |
| Olympia / Tumwater | 2,047 | 'Leaf emergence' | — | — |
| Tacoma / Puyallup | 2,016 | 'Leaf emergence' | — | — |
| Bellingham / Whatcom | 1,994 | 'Leaf emergence' | — | — |
| Sequim / Rain Shadow | 1,926 | '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 | '' |
Source: 'NPN citizen science observations (WA+OR), n=10, median. services.usanpn.org' About GDD₃₂ →
Season tracker for Kent / Auburn as of May 14, 2026. Predicted dates use 16-day weather forecast through May 30, 2026, then climate normals.