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Acer shirasawanum 'Aureum'
Golden Full Moon Maple
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Overview
Acer shirasawanum 'Aureum' is a deciduous tree reaching 15–20 feet (4.5–6 m) tall with a spread of 12–18 feet (3.7–5.5 m) over 15–20 years, forming a rounded to broadly oval crown. Leaves are nine- to eleven-lobed, 3–5 inches (7.5–13 cm) wide, with pointed lobes and finely serrated margins — rounder in overall outline than A. palmatum leaves, resembling a full moon, giving the species its common name. Foliage emerges bright golden-yellow in spring and holds yellow to chartreuse-yellow through summer — one of very few maples with persistently non-green summer foliage at this scale. Fall color is orange to red. Small reddish-purple flowers appear in pendant corymbs in April–May. Samaras, 0.75–1 inch (2–2.5 cm) long, ripen in September–October. Growth rate is slow, 6–8 inches (15–20 cm) per year. White-variegated sectors in the yellow leaves are susceptible to scorch in afternoon sun above 85°F (29°C); partial shade is required in most climates.
Native Range
Acer shirasawanum is native to the mountains of Japan, occurring in cool, moist mixed forests on Honshu at elevations of 3,000–6,600 feet (900–2,000 m). The 'Aureum' cultivar has been in cultivation in Japan for several centuries and does not occur in wild populations.Suggested Uses
Planted as a specimen in Japanese-style gardens, woodland gardens, and mixed shrub borders at 12–15 foot (3.7–4.5 m) spacing. The persistent golden-yellow summer foliage is the primary design feature. Suited to sheltered positions with afternoon shade in most climates. Not suited to hot-summer climates without afternoon shade, alkaline soils, or exposed windy sites.How to Identify
Appearance
Size & Dimensions
Height15' - 20'
Width/Spread12' - 18'
Reaches mature size in approximately 18 years
Bloom Information
Small reddish-purple flowers appear in pendant corymbs in April–May as new leaves emerge. Individual flowers are 0.3–0.4 inch (8–10 mm) across. Samaras, 0.75–1 inch (2–2.5 cm) long, ripen in September–October.Detailed Descriptions
Foliage Description
golden-yellow to chartreuse-yellow spring through summer; orange to red in fallGrowing Conditions
Sun Requirements
Requires 2-6 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
Care & Maintenance
Care Guide
Plant in moist, well-drained, humus-rich soil with a pH of 5.5–6.5 in partial shade — morning sun with afternoon shade is standard in most climates. Full sun is tolerated in the Pacific Northwest and coastal zones with summer highs below 80°F (27°C); elsewhere afternoon shade is required to prevent leaf scorch. Water weekly during the first two growing seasons and through summer dry spells; established plants tolerate dry intervals of 7 days. Summer temperatures above 85°F (29°C) cause scorch on the yellow leaf tissue. Not suited to hot-summer climates in zones 7b–8 without consistent afternoon shade. No routine fertilization is required in humus-rich soils.Pruning
No routine pruning is required. The rounded crown is self-maintaining. Prune in late spring to early summer (May–June) after leaf-out if shaping is needed. Remove dead or crossing branches. Avoid late summer or fall pruning. Do not remove the central leader in young trees.Pruning Schedule
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F
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A
M
J
J
A
S
O
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D
late spring
Maintenance Level
lowContainer Growing
✓ Suitable for container growing
Minimum container size: 15 gallons
⚠️ Toxicity Warning
Non-toxicBotanical Flashcard
