Japanese Maple
Acer palmatum Thunb.
Érable palmé
Scientific Name: Acer palmatum Thunb.
Common Names: Japanese Maple
Family: Sapindaceae (Soapberry family)
Native Range: Eastern Asia (Japan, Korea, China)
Introduced Range: Widely cultivated worldwide, common in North American landscapes
Canadian Plant Hardiness Zones: CA6+

Size & Growth
Typical Height: 4–10 m (13–33 ft)
Maximum Recorded Height: ~16 m (52 ft)
Trunk Diameter: Typically <30 cm (12 in), can reach ~45 cm (18 in)
Growth Rate: Slow to moderate
Typical Lifespan: 100+ years under good conditions
Record Age: Likely over 150 years in optimal settings
Leaves: 5–9 deeply lobed, double-toothed, taper-pointed, turning yellow, bronze, or red in autumn
Bark: Smooth, grayish-brown when young, may become slightly rough with age
Twigs: Slender, green in summer, turning red in autumn, often waxy
Fruits: Winged samaras (keys), 12–15 mm long, incurved at ~100° angle, red in autumn
Buds: Small, green or red, in pairs at shoot tips, surrounded by a raised leaf scar

Reproduction & Life Cycle
Seed Maturity: ~10 years
Reproductive Cycle: Annually
Pollination Method: Wind, Insects
Seed Dispersal Mechanism: Wind
Seed Dormancy Requirements: Cold stratification needed (~90 days)
Soil Preferences: Well-drained, rich, slightly acidic to neutral soils
Water Needs: Moderate, prefers moist conditions but well-draining soil
Drought Tolerance: Moderate (somewhat drought-sensitive, benefits from supplemental watering)
Flood Tolerance: Low (sensitive to waterlogging)
Shade Tolerance: Partial shade preferred; some cultivars tolerate full sun
Root System Type: Fibrous, shallow
Climate Adaptability: Prefers temperate climates; struggles in extreme heat or cold
Physical & Chemical Properties
Wood Density: ~540 kg/m³ (34 lb/ft³)
Strength Rating: Low (not used for timber)
Decay Resistance: Low (prone to rot if exposed to moisture)
Fire Resistance: Low
Fire Regeneration Ability: None (not fire-adapted)

Ecological Role & Interactions
Wildlife Value: Limited; some birds and small mammals eat the seeds
Companion Species: Commonly grown with azaleas, rhododendrons, and other shade-loving plants
Invasive Status: Not invasive but naturalizes in some areas
Threats: Pests (aphids, scale, spider mites), diseases (verticillium wilt, powdery mildew), climate change (drought sensitivity)
Traditional Uses: Ornamental tree cultivated for centuries in Japan, often in temple gardens
Modern Uses: Landscaping, bonsai, artistic pruning (e.g., cloud pruning)
Symbolism/Mythology: Represents peace, balance, and elegance in Japanese culture
Unique Features: Over 1,000 cultivars exist, ranging in leaf color, shape, and tree form
Interesting Historical Facts: Some ancient Japanese maples have been cultivated for centuries
Rare/Endangered Varieties: Some older cultivars are difficult to find in the nursery trade.