Acer macrophyllum, bigleaf maple
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Broadleaf Deciduous Trees

Acer macrophyllum

bigleaf maple

Sapindaceae

Western North America, southern Alaska to Baja California

At a Glance

TypeTree
HabitSpreading
FoliageDeciduous
Height50-100 feet (15-30 m)
Width30-50 feet (9-15 m)
Maturity30 years

Growing Zones

USDA Hardiness Zones

5 - 9
Zone 5
Zone 6
Zone 7
Zone 8
Zone 9
These zones indicate the coldest temperatures this plant can typically survive.
Frost Tolerancehardy

Key Features

Attracts Pollinators
Native to North America
Maintenancelow

Overview

Acer macrophyllum is a large deciduous tree reaching 50–100 feet (15–30 m) tall and 30–50 feet (9–15 m) wide at maturity, with a broad, rounded crown. Leaves are palmate with 3–5 deeply cut lobes, 6–12 inches (15–30 cm) across — the largest leaves of any maple species — dark green above and pale green beneath, turning yellow to golden yellow in fall. Bark is gray-brown and furrowed on mature trees; younger branches are smooth and gray-green. In April, pendulous clusters of yellow-green flowers 4–6 inches (10–15 cm) long appear before or with the leaves. Winged samaras, 1.5–2 inches (4–5 cm) long, are produced in pairs and ripen in fall. In moist, shaded conditions, the bark and larger branches commonly support mosses, lichens, and epiphytic ferns, including licorice fern (Polypodium glycyrrhiza). Growth rate is fast in youth, 2–3 feet (60–90 cm) per year in favorable sites; slowing with age. Surface roots become prominent under paved areas and in compacted soils, potentially damaging infrastructure. The tree requires considerable space and is unsuitable for small lots.

Native Range

Native to western North America from southern Alaska south through British Columbia, Washington, Oregon, and California to Baja California. Found from sea level to 5,500 feet (1,680 m) elevation in moist forests, stream banks, canyon bottoms, and lower mountain slopes.

Suggested Uses

Suited to large landscapes, parks, riparian restoration plantings, and naturalistic woodland gardens with a minimum of 50 feet (15 m) horizontal clearance from structures. Provides deep shade; lawn grass establishment is difficult within the drip line. Used in stream bank stabilization and habitat restoration in the Pacific Northwest. Not suited for small residential lots or planting near infrastructure.

How to Identify

Identified by its exceptionally large palmate leaves, 6–12 inches (15–30 cm) across with 3–5 deeply cut lobes — larger than any other maple. Paired winged samaras 1.5–2 inches (4–5 cm) long have coarse, bristly hairs on the seed body. Bark on mature trees is gray-brown and furrowed. Pendulous yellow-green flower clusters appear in April before leaf-out is complete. In moist conditions, bark frequently hosts mosses and licorice fern.

Appearance

Size & Dimensions

Height50' - 100'
Width/Spread30' - 50'

Reaches mature size in approximately 30 years

Colors

Flower Colors

yellow
green

Foliage Colors

dark green

Fall Foliage Colors

yellow
gold

Bloom Information

Bloom Period

~3 weeks
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Spring
Blooms in April, with pendulous yellow-green flower clusters 4–6 inches (10–15 cm) long emerging before or concurrent with leaf expansion. Individual flowers are small, 0.25 inch (6 mm); clusters last 2–3 weeks. Samaras mature and disperse September through October. Bloom timing varies by elevation: lower-elevation trees bloom 2–3 weeks earlier than mountain populations.

Detailed Descriptions

Flower Description

yellow-green

Foliage Description

dark green above, pale green beneath; yellow to golden yellow in fall

Growing Conditions

Sun Requirements

Full Sun
Partial Shade
Requires 4-8 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range5.0 - 7.0(Neutral)
357912
Soil Types
loamclaysilt
Drainage
moist

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Time to Maturity

20-40 years

Care & Maintenance

Care Guide

Establish with regular watering for the first 2–3 years; once established, the tree is largely self-sufficient in the Pacific Northwest where annual rainfall exceeds 30 inches (75 cm). In drier regions or during summer drought, deep watering every 2–3 weeks reduces stress and leaf scorch. Avoid planting within 10 feet (3 m) of paving, foundations, or utilities due to surface root spread. Verticillium wilt can infect wounded trees; avoid soil disturbance within the drip line. Aphids are common on new growth in spring and produce honeydew that supports sooty mold; natural predators typically control populations. Large branches require professional removal due to size and weight.

Pruning

Prune during dormancy (November through January) or in summer (July–August) to reduce the risk of bleeding sap and fungal entry through cuts. Remove dead, damaged, or crossing branches. Branches over 2 inches (5 cm) in diameter should be removed at the collar and treated promptly. This species grows large; structural pruning when young (years 3–10) reduces the need for costly corrective work later. Avoid pruning in spring when sap flow is active.

Pruning Schedule

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wintersummer

Maintenance Level

low

⚠️ Toxicity Warning

Non-toxic