Acer Crimson King / Red Norway Maple

Common Name: Crimson King Maple, Purple Norway Maple

Botanical Name: Acer platanoides ‘Crimson King’

Family: Sapindaceae

Origin: Cultivar selection of European species

Mature Height: 12-15 metres

Mature Spread: 10-12 metres

Growth Rate: Moderate to fast (40-50cm per year)

Foliage: Deciduous; large, five-lobed leaves emerge deep crimson-purple in spring, maturing to rich purple-maroon through summer, deepening to purple-red in autumn

Flowers: Clusters of small yellow flowers in April, creating a striking contrast against emerging purple foliage

Fruit: Winged seeds (samaras) in autumn, held in pairs; often tinged with purple

Soil Requirements: Highly adaptable; thrives in clay, loam, chalk, or sandy soils; tolerates alkaline and acidic conditions; prefers well-drained to moist soil

Light Requirements: Full sun (essential for best colour – shade causes foliage to turn greenish)

Hardiness: Fully hardy; tolerates urban pollution, wind, and exposed sites

Special Features: Year-round deep purple foliage; dramatic colour contrast in mixed planting; striking yellow flowers against dark leaves; excellent shade tree; tolerates urban conditions; fast-growing for impact

‘Crimson King’ is not a tree for the timid – this is a maple that commands attention and transforms the landscape with its deep, brooding colour. From the moment the leaves unfurl in spring as rich crimson-purple, through summer’s dark maroon depths, to autumn’s purple-red finale, this tree provides continuous, dramatic colour that few others can match.

The foliage is the star – large, five-lobed leaves that emerge in spring as deep crimson, creating an immediate impact that signals the growing season’s arrival. As the leaves mature, they deepen to a rich purple-maroon that holds its intensity through the summer months, providing a dark, sophisticated backdrop for lighter planting. In full sun, the colour is deep and saturated; in shade, it tends toward greenish-purple, so site selection is crucial for maximum impact.

Spring brings an unexpected delight – clusters of small, bright yellow flowers appear just as the purple leaves emerge, creating a striking colour contrast that’s both unusual and beautiful. The flowers are attractive to early pollinators and add an extra layer of interest before the canopy fully develops.

The tree’s naturally rounded, dense crown provides substantial shade, making it ideal for cooling patios, framing seating areas, or creating dark, dramatic focal points in larger gardens. The purple foliage makes other colours sing – silvers shimmer against it, lime greens glow, and whites appear luminous. It’s a tree that elevates everything around it through contrast and presence.

‘Crimson King’ is remarkably adaptable and tolerant of urban conditions. It thrives in compacted soil, handles pollution with ease, and tolerates both alkaline and acidic conditions. The growth rate is faster than many maples, allowing you to achieve impact within a reasonable timeframe.

For wildlife, the flowers provide early nectar, the dense canopy offers nesting sites, and the seeds feed birds in autumn. The tree’s robust nature and tolerance of challenging conditions make it a reliable choice for parks, streets, and larger gardens where bold colour is desired.

This is a tree for those who embrace drama and aren’t afraid of making a statement – a living exclamation mark in the landscape.

Choose a site in full sun – this is absolutely essential for the best foliage colour. Shade or partial shade will cause the leaves to turn greenish-purple, losing the dramatic impact that makes this cultivar so special. The site should have well-drained to moist soil; ‘Crimson King’ is highly adaptable and will thrive in clay, loam, chalk, or sandy conditions.

Allow generous space for the mature canopy – at least 10-12 metres from buildings, boundaries, and other large trees. The dense shade cast by the purple foliage means underplanting options are limited, so consider this when planning the location.

Dig a planting hole twice the width of the root ball but no deeper. Position the tree so the top of the root ball sits level with the surrounding soil. Backfill with excavated soil, firm gently, and water thoroughly. Stake young trees for the first 2-3 years using a single angled stake and flexible tree tie.

Apply a 5-7cm layer of organic mulch around the base, keeping it clear of the trunk.

Plant bare-root or root-balled specimens from November to March, or container-grown trees year-round (though autumn and spring establishment is preferable).

Water regularly during the first two growing seasons to establish a deep root system. Once established, ‘Crimson King’ is reasonably drought-tolerant but performs best with occasional deep watering during prolonged dry periods.

Apply a balanced slow-release fertiliser in early spring for the first few years. Mature specimens require minimal feeding – simply maintain the mulch layer to conserve moisture and suppress weeds.

‘Crimson King’ requires minimal pruning and naturally develops a well-balanced, rounded crown. Remove any dead, damaged, or crossing branches in late autumn or winter (November-February) when the tree is fully dormant and sap flow is minimal.

Avoid heavy pruning, as maples can bleed sap profusely if cut during the growing season. If formative pruning is needed, do so in winter and make clean cuts just outside the branch collar.

Remove any shoots with green foliage promptly – these are reversions to the species and will eventually dominate if left unchecked.

Check and adjust tree ties regularly during the first few years to prevent rubbing or constriction.

Winter: Bold architectural branch structure; dark buds swell dramatically from February onwards.

Spring: Leaves emerge as striking crimson-purple; clusters of bright yellow flowers create dramatic contrast in April.

Summer: Dense canopy of rich purple-maroon foliage provides deep shade and continuous colour; dramatic presence in the landscape.

Autumn: Foliage deepens to purple-red before falling; winged seeds (often purple-tinged) provide decorative detail.

The deep purple foliage of ‘Crimson King’ creates stunning contrasts with lighter colours. Plant with silver-leaved plants such as Elaeagnus ‘Quicksilver’, Pyrus salicifolia ‘Pendula’, or Artemisia for shimmer and contrast.

Lime-green foliage – Robinia pseudoacacia ‘Frisia’, Philadelphus coronarius ‘Aureus’, or Choisya ternata ‘Sundance’ – glows against the dark background.

White-flowering plants appear luminous beneath or near the purple canopy – Hydrangea paniculata, white roses, or Philadelphus create striking combinations.

The dense shade beneath mature specimens limits underplanting options – choose shade-tolerant evergreens such as Sarcococca, Pachysandra, or Vinca minor for ground cover.

Generally healthy and trouble-free. Occasionally affected by aphids in spring (usually not requiring treatment) or tar spot fungus (cosmetic only, does not harm the tree). Good air circulation helps prevent fungal issues.

Watch for green-leaved shoots (reversions) and remove promptly to maintain the purple foliage characteristic.

Our ‘Crimson King’ Maples are carefully selected to ensure deep, consistent colour and strong, well-structured specimens. Whether you’re creating a dramatic focal point, establishing bold colour contrast in mixed planting, or seeking a shade tree with year-round impact, ‘Crimson King’ offers unmatched presence and sophistication. This is a tree for those who garden with confidence and appreciate the power of dark, dramatic colour in the landscape.