Botanical Classification
Crimson King Maple is a cultivar of Norway Maple, scientifically known as Acer platanoides. It belongs to the family Sapindaceae, under the genus Acer, which encompasses all maples. As a broadleaf deciduous tree, Crimson King is not a distinct species but a specially cultivated variety known for its striking deep purple foliage. Its classification is as follows:
- Kingdom: Plantae
- Order: Sapindales
- Family: Sapindaceae
- Genus: Acer
- Species: Acer platanoides
- Cultivar: ‘Crimson King’
History and Origin
The Crimson King Maple was developed in Europe during the mid-20th century as a cultivar of the Norway Maple (Acer platanoides), a species native to eastern and central Europe and western Asia. Norway Maples were first introduced to North America in the 1700s as ornamental and shade trees, prized for their adaptability and tolerance of urban conditions. The Crimson King variety was specifically selected and cultivated for its dense, symmetrical crown and distinctive burgundy foliage, which sets it apart from green-leaved maples. It quickly gained popularity in residential and municipal landscaping in North America and parts of Europe.
Identifying Characteristics
Crimson King Maple is easily identified by its bold purple-maroon leaves, which maintain their deep color throughout the growing season—unlike other maples that may only exhibit colorful foliage in autumn. Its leaves are opposite, palmately lobed, with five sharply pointed lobes and smooth margins. The bark is gray-brown and develops shallow furrows with age. It grows with a rounded to oval crown, forming a dense canopy that provides ample shade. The tree produces yellow-green flowers in early spring before leaf-out, which contrast beautifully with the emerging dark foliage. Although not showy individually, the flowers appear in clusters and can attract pollinators.
Growth Rate and Lifespan
Crimson King Maple has a moderate growth rate, typically gaining 12 to 24 inches per year under good conditions. At maturity, it generally reaches 35 to 50 feet tall and 25 to 40 feet wide, with a full and uniform crown. In urban environments, it may be shorter due to space limitations. The tree is long-lived, with a potential lifespan of 60 to 100 years, although this may be shortened in high-stress environments or if not properly maintained. It has a shallow root system, which can affect lawns or pavements nearby.
USDA Zones and Distribution
Crimson King Maple is hardy in USDA Zones 3 to 7, making it well-suited to a broad range of temperate climates, including much of the northern and central United States and southern Canada. It performs best in cool to moderate climates, where hot and humid summers are less frequent. While the parent species, Norway Maple, has naturalized in parts of North America and is considered invasive in some regions, the Crimson King cultivar is usually confined to landscape plantings and is less likely to spread aggressively, although it can still produce viable seeds.
Habitat Preferences
In the wild, the species prefers moist, well-drained soils, but Crimson King Maple shows impressive adaptability to a variety of soil types, including clay, loam, and even compacted urban soils. It can tolerate drought, air pollution, and salt, making it especially useful in cities, along streets, and in parking lots. It prefers full sun to partial shade, though its foliage color is most vibrant in full sun. The tree does not thrive in soggy or overly alkaline soils and is best suited to temperate woodland edge or open landscape habitats.
Landscape Uses
- Accent or specimen tree for its dramatic purple foliage
- Shade tree in parks, lawns, and large residential properties
- Street tree where space allows for its wide crown
- Visual contrast in gardens when planted near green-leaved trees
- Windbreaks or screening due to its dense canopy
- Adds season-long color interest, especially in monochrome landscapes
Common Problems
- Shallow roots can damage sidewalks and outcompete lawn grass
- Leaf scorch in extreme heat or drought, especially in dry climates
- Susceptible to tar spot, a fungal disease that causes black leaf spots
- Prone to verticillium wilt, a soil-borne fungal disease
- Invasive tendencies of the parent species (Norway Maple) are a concern in some regions
- Poor fall color, usually dull yellow or brown instead of bright red or orange
- Heavy shade limits undergrowth and turf growth beneath the canopy
- Seedlings may become weedy in some areas, though less so than wild Norway Maple
- Weak wood can lead to branch breakage under snow or ice loads
- Girdling roots may develop in poorly planted specimens
Cultivation of Crimson King Maple (Acer platanoides ‘Crimson King’)
Soil Requirements
- Prefers well-drained, fertile loam but tolerates a range of soils including clay and compacted urban soils.
- Can handle moderately acidic to slightly alkaline pH levels.
Light Conditions
- Thrives in full sun for best foliage color.
- Tolerates partial shade, though leaf color may fade slightly.
Watering Needs
- Requires regular watering during establishment (first 1–2 years).
- Once established, it is moderately drought-tolerant but benefits from consistent moisture.
Planting Season
- Best planted in spring or fall, when temperatures are cooler and soil moisture is more stable.
Spacing
- Requires 30 to 40 feet of spacing from other trees or structures to accommodate mature spread.
- Avoid planting near sidewalks or driveways due to shallow roots.
Growth Rate
- Moderate growth rate of 12–24 inches per year under favorable conditions.
Fertilization
- Apply a balanced slow-release fertilizer in early spring if soil nutrients are low.
- Avoid over-fertilizing, which can cause weak growth.
Pruning
- Prune in late winter or early spring to remove dead, damaged, or crossing branches.
- Maintain a strong central leader to prevent poor structure.
Mulching
- Use a 2–3 inch mulch layer around the base to retain moisture and suppress weeds.
- Keep mulch away from the trunk to prevent rot.
Cold Hardiness
- Hardy in USDA Zones 3 to 7. Can withstand cold winters, snow, and frost.
Pest and Disease Management
- Monitor for tar spot, verticillium wilt, and aphids.
- Use proper sanitation and avoid overwatering to reduce disease risk.
Urban Suitability
- Well-suited for urban planting due to its tolerance of pollution and salt.
- Ideal for streetscapes, lawns, and large open areas.
Propagation
- Typically propagated via grafting onto Norway Maple rootstock to preserve cultivar traits.
- Seeds do not reliably produce true-to-type Crimson King offspring.