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Acer platanoides 'Crimson King'
Crimson King maple
Cultivar; parent species native to Europe and western AsiaLearn more
Overview
Acer platanoides 'Crimson King' is a cultivar of Norway maple reaching 35–50 feet (10–15 m) tall and 25–40 feet (7.5–12 m) wide, with a dense, oval to rounded crown similar in form to the species. Leaves are palmate with 5–7 pointed lobes, 4–7 inches (10–18 cm) across, dark maroon-purple from emergence in spring through leaf drop in fall — the defining trait of this cultivar. Foliage color intensifies in full sun; plants in shade develop a more greenish-purple tone by midsummer. As with the species, breaking a leaf petiole releases milky white sap. In early spring, crimson-yellow flowers appear in erect clusters before or with leaf emergence. Paired samaras ripen in fall; seedlings produced are green-leaved, reverting to the species type rather than the purple-leaved cultivar. Growth rate is moderate, 1–1.5 feet (30–45 cm) per year — slightly slower than the species. Surface roots are aggressive and compete with turf and adjacent plantings. Acer platanoides, including 'Crimson King', is listed as invasive in numerous US states and Canadian provinces; seedlings establish readily in forest understories and displace native vegetation.
Native Range
This cultivar has no native range. The parent species, Acer platanoides, is native to Europe and western Asia, from Norway south to the Caucasus and east to the Ural Mountains.Suggested Uses
Planted as a large shade tree or specimen for foliage color contrast in parks, commercial landscapes, and large residential properties. Use away from natural areas, forest edges, and riparian corridors where seedling escape is a concern. Its use is regulated or discouraged in several US states due to the invasive potential of A. platanoides; consult local guidelines before planting.How to Identify
Appearance
Size & Dimensions
Height35' - 50'
Width/Spread25' - 40'
Reaches mature size in approximately 20 years
Bloom Information
Blooms late March through April, with erect clusters of crimson-yellow flowers 2–3 inches (5–8 cm) across appearing before or concurrent with leaf emergence. The flower display lasts 2–3 weeks. Samaras ripen September through October and disperse by wind; germination of seedlings is prolific the following spring, with seedlings producing green (not purple) foliage.Detailed Descriptions
Foliage Description
dark maroon-purple spring through fallGrowing Conditions
Sun Requirements
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
Care & Maintenance
Care Guide
Water weekly for the first 1–2 growing seasons; established trees tolerate drought, compacted soils, road salt, and air pollution. Foliage holds the deepest maroon-purple tones in full sun locations; part-shade plants develop a more greenish-purple appearance by late summer. Avoid planting within 8–10 feet (2.4–3 m) of pavement or structures due to aggressive surface roots. Monitor adjacent natural areas and remove green-leaved seedlings promptly — they revert to the invasive species type. Verticillium wilt causes branch dieback; remove affected limbs and avoid root zone disturbance.Pruning
Prune during dormancy (November through February) or in summer (July–August) to reduce sap bleeding from wounds. Remove dead, damaged, or crossing branches. Avoid heavy pruning; large wounds bleed freely. Structural pruning of young trees in years 3–10 reduces the need for corrective work later. Do not prune in spring during active sap flow.Pruning Schedule
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