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Acer platanoides 'Crimson King'
Crimson King maple
Cultivar; parent species {Acer platanoides} native to Europe and western Asia from Norway south to the Caucasus and east to the Ural Mountains
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Overview
Acer platanoides 'Crimson King' is a cultivar of Norway maple in the family Sapindaceae, 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. The defining character is foliage color: leaves are palmate with 5-7 pointed lobes, 4-7 inches (10-18 cm) across, and emerge dark maroon-purple in spring, holding the color from emergence through leaf drop in fall without the mid-summer greening that develops on some other purple-leaved maples. Color saturation is highest in full-sun positions; plants in shade develop a greenish-purple tone by midsummer. As with the species, a broken petiole releases milky white sap. In early spring, crimson-yellow flowers open in erect clusters before or with leaf emergence. Paired samaras ripen in fall; seedlings produced are green-leaved and revert to the species type rather than reproducing the purple cultivar. Growth is moderate at 1-1.5 feet (30-45 cm) per year — somewhat slower than the species. Surface roots compete with turf and adjacent plantings. The parent species A. platanoides, including the cultivar 'Crimson King', is listed as invasive in numerous U.S. states and Canadian provinces, where seedlings establish readily in forest understories and displace native vegetation.
Native Range
The cultivar 'Crimson King' 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, where it grows in mixed deciduous and montane forests on fertile moist soils.Suggested Uses
Planted as a large shade tree or foliage-color specimen in parks, commercial landscapes, and large residential properties. Sited away from natural areas, forest edges, and riparian corridors where seedling escape to the invasive species type is a concern. Planting is regulated or discouraged in several U.S. states because of the invasive potential of A. platanoides; local guidelines are consulted before planting. Combined with silver-foliaged or chartreuse plantings for color contrast in large mixed borders. Not suited to small residential yards, narrow planting strips, positions within 8-10 feet (2.4-3 m) of pavement, or sites adjacent to wildlands.How to Identify
Appearance
Size & Dimensions
Height35' - 50'
Width/Spread25' - 40'
Reaches mature size in approximately 20 years
Bloom Information
Erect clusters of crimson-yellow flowers 2-3 inches (5-8 cm) across open in late March through April before or concurrent with leaf emergence, averaging 2-3 weeks of bloom. The red-and-yellow color contrasts with the emerging dark purple foliage. Samaras ripen September through October and disperse by wind; seedling germination the following spring is prolific and produces green (not purple) foliage that matches the species type.Detailed Descriptions
Flower Description
crimson-yellow; erect clusters 2-3 inches (5-8 cm) acrossFoliage Description
dark maroon-purple from spring emergence through fall leaf drop; palmate leaves 4-7 inches (10-18 cm) across with 5-7 pointed lobesGrowing 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
Plant in well-drained soil with a pH of 4.5-7.5 in full sun where the dark purple foliage color holds strongest; in part shade the cultivar develops a greenish-purple tone by late summer. Tolerated soil types include loam, clay, sand, and silt. Water weekly for the first 1-2 growing seasons. Established trees tolerate drought, compacted urban soils, road salt, and air pollution. Pavement or structures within 8-10 feet (2.4-3 m) are damaged by aggressive surface root spread. Adjacent natural areas are monitored for green-leaved seedlings that should be removed promptly because they revert to the invasive species type. Verticillium wilt causes branch dieback — affected limbs are removed and root-zone disturbance is minimized.Pruning
Pruning is done in dormancy (November through February) or in summer (July-August) to reduce sap bleeding from wounds. Dead, damaged, or crossing branches are removed at these times. Heavy pruning is avoided because large wounds bleed freely. Structural pruning of young trees in years 3-10 reduces the need for corrective work later. Spring pruning is avoided because sap pressure is highest at that time and wounds bleed heavily.Pruning Schedule
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