Updated: Oct 23, 2021
Big leaves, big tree, at least that is how I remember this tree from my parent's property when they lived in Washington State. The driveway wound around its massive trunk, and the canopy shaded all the understory plants. When the leaves fell in autumn, Mom would collect the best ones, often reaching almost a foot across. I have not seen such large leaves since.
Before returning to the South Bay/Peninsula of my youth, I lived in Sonoma County where the bigleaf maples were the first to turn bright yellow along Highway 116 near the coast. In those moments, I knew fall was coming, but the leaves could never match what I saw further north. Bay Area leaves were about 8" across, as shown in this example, and still large for comparative maple species.
To be candid, I have not seen any large specimens in California. That is when I rely on Cal Poly's Urban Forest Ecosystems Institute Big Tree Registry, so I can be reminded of the potential each tree has under the right conditions. For California, the registry lists an A. macrophyllum in Humboldt County reaching over 75' with a crown spread of 84' and a substantial trunk. No doubt the cool of the region supports its performance over time, but I wonder just how large they can become in more southern locations.
Shown below one specimen planted at West Valley College. The college has introduced several more, so I look forward to seeing their growth. This young example is multi-trunked, which usually means the tree will not reach the more prominent size. How large? Only time will tell.
West Valley College Campus Location: Acer macrophyllum
Cilker (north face)
Long: 122° 0'40.56"W
All photos except the yellow leaf are from the West Valley College specimen. The yellow leaf was photographed in central Washington State.
Botanical Name: Acer macrophyllum
Acer: Traditional Latin name for maple
Macrophyllum: Large leaves
Common Name: Bigleaf maple
Family Name: Sapindaceae
Origin: Coastal Native - Southern Alaska to Southern California
Positioning: Woodland, lawn, riparian, large spaces
Garden Themes: Native, shade, autumn, rain
Uses: Shade tree, specimen, green stormwater infrastructure (not recommended for C.3 soil specifications)
Type: Deciduous tree
Form: Oval to round
Size: 30' to 50' wide x 30' to 75' tall
Outstanding Feature(s): Fall color (leaf), size potential
Bark: Red-brown when young turning dark brown/gray and fissured with age.
Shape: Palmate, lobed
Margin: Entire but irregular with shallow lobes
Color: Medium green, slightly lighter underneath turning yellow in fall
Surface: Slightly hairy, visually unnoticeable but feels like light velvet
Flower: Spring. Small clusters, green and slightly fragrant.
Fruit: Summer. Samara, green turning brown.
cultural requirements, tolerances & problems
Sunset Zones: 2-9, 14-24
USDA Zones: 6-7
Light: Full sun to full shade (fall color performs best with afternoon shade)
WUCOLS SF Bay Area Hydro Zone: Moderate
Texture: Sand, loam, well-composted
Moisture Retention: Moist but well-drained
pH: Highly acidic to slightly alkaline
Tolerances: Brief heat, humidity
Branch Strength: Medium
Insects: Borers, caterpillars
Disease: Sudden oak death, armillaria, root rot
First People uses include(d) materials for basketry, paddles, textiles, firewood, and house construction, according to the California Oak Mortality Task Force and other sources.
citations & attributions
Norris Brenzel, K. (Ed.). (2012). The New Sunset Western Garden Book. New York: Time Home Entertainment, Inc.
NC State Extension. "Acer macrophyllum." North Carolina State University, Raleigh. Accessed on June 27, 2021, from https://plants.ces.ncsu.edu/plants/acer-macrophyllum/.
Urban Forest Ecosystems Institute SelecTree. "Acer macrophyllum Tree Record." 1995-2021. Cal Poly State University, San Luis Obispo. Accessed on June 27, 2021. https://selectree.calpoly.edu/tree-detail/58.
Water Use Classification of Landscape Species. "WUCOLS IV Plant List." University of California, Division of Agriculture and Natural Resources, Davis. Accessed on June 27, 2021.