Coral bark maple

Sun

Full sun to partial shade; morning sun and afternoon shade are best where summers are hot.

Water

Keep the root zone evenly moist but not waterlogged. Water deeply during dry spells, particularly while establishing and when grown in a container.

Soil

Moist, well-drained soil rich in organic matter, preferably slightly acidic to neutral. Avoid waterlogged ground and shallow, drought-prone soil.

Height

20-25 ft (6-7.6 m)

Spread

15-20 ft (4.6-6 m)

Flowers

Small reddish-purple flowers in spring; inconspicuous beside the emerging leaves.

Foliage

Finely pointed, usually five- to seven-lobed leaves emerge light green, sometimes with reddish margins, deepen to green in summer, then turn yellow to golden orange in autumn.

Growth

Slow to moderate; slower in containers or dry conditions.

Care needed

Medium

• Pollinators
• Wildlife

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Moderate

Toughness

Fairly tough

Pick your zone, country, light and whether you have pets.

1. Planting day

   7 ft (2 m)

2. After 1 year

   7 ft (2.2 m)

3. After 2 years

   8 ft (2.4 m)

4. After 3 years

   8 ft (2.6 m)

5. After 5 years

   10 ft (2.9 m)

About 26 years to full size.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Safe

Growth rate

Slow

• Plant with the root flare at soil level and the graft union above the soil.
• Water deeply through the first two growing seasons, checking soil moisture rather than watering on a fixed schedule.
• Spread 2-3 in (5-8 cm) of organic mulch over the root zone, keeping it clear of the trunk.
• Feed lightly in spring only if growth is weak; avoid heavy nitrogen feeding and late-season fertiliser.
• Shelter from drying winds, and protect container roots from severe winter cold.
• Remove any shoots growing from below the graft union.

Pruning. Prune sparingly in late summer while the tree is in leaf, removing crossing branches and shortening awkward shoots back to a suitable side branch. Remove dead wood when identified; do not cut the tree back hard to force brighter bark.

Spring

Check emerging leaves after late frost; leave damaged growth until healthy buds show where to trim.

Spring

Refresh mulch and apply a light feed only if the tree needs it.

Summer

Check soil moisture during dry weather and water deeply before leaves begin to scorch.

Late summer

Carry out light corrective pruning and remove shoots below the graft.

Autumn

Plant while soil is workable and moist, or wait until spring in very cold regions.

Winter

Insulate containers against hard freezes and check that the soil does not dry out completely.

• Place where winter light catches the red branches, with a dark evergreen hedge behind them.
• Use as a specimen beside a patio or path, leaving room for its mature canopy.
• Underplant in a sheltered woodland garden with ferns, hellebores and low evergreen groundcover.
• Grow in a large, frost-resistant container in a sheltered courtyard, allowing for regular watering and eventual repotting.

Garden styles it suits: Japanese, Woodland, Modern courtyard, Winter interest, Autumn colour and Pacific Northwest woodland.

Plant it with: Hellebores, Epimediums, Japanese forest grass, Christmas fern, Camellias and Snowdrops.

Wildlife: The small flowers provide some food for insects, and the branches offer shelter and perching places for birds. It generally supports fewer specialist insects than locally native maples.

• Leaf scorch: dry soil, hot afternoon sun and wind cause brown leaf edges. Water deeply, mulch and provide afternoon shade; damaged leaves will not recover.
• Verticillium wilt: sudden wilting or branch dieback can indicate this soilborne disease. Seek a diagnosis, remove dead branches and avoid replanting another susceptible tree in the same spot.
• Root rot: poorly drained soil causes weak growth and root decline. Correct drainage and keep the root flare exposed; badly affected trees may need replacing.
• Scale insects: inspect stems for small fixed bumps, sticky honeydew and sooty mould. Remove light infestations by hand and use a locally approved horticultural oil when appropriate, avoiding heat and tender new foliage.

Not known to be toxic to cats, dogs or people; no part is recognised as a significant poisoning hazard for these groups. Horse-specific safety information is limited, so keep fallen leaves and prunings out of paddocks and feed. Do not confuse it with red maple, Acer rubrum, whose wilted leaves can be fatal to horses.

Where it spreads. Japanese maple can self-seed and escape into woodland in parts of the eastern United States, particularly the Mid-Atlantic. This concern applies to the species; 'Sango-kaku' is not generally treated separately. Remove unwanted seedlings near natural areas.

• Beni-kawa Japanese maple (Acer palmatum 'Beni-kawa')

  Another green-leaved maple with red winter bark, often growing more slowly and remaining smaller. Bark colour overlaps, so a reliable nursery label is the best way to distinguish young plants.

• Japanese maple (Acer palmatum)

  Ordinary seedlings have similarly lobed leaves but lack the consistent coral-red winter colour on young branches.

• Coral bark willow (Salix alba 'Britzensis')

  Has narrow, unlobed leaves and yellow-orange to red winter stems; it grows much faster and tolerates wetter soil.

Palmatum refers to the hand-shaped leaves, while the Japanese cultivar name 'Sango-kaku' is commonly translated as 'coral tower', referring to the coloured branches.

Propagation. Usually propagated by grafting onto Japanese maple rootstock. Seedlings do not reliably retain the coral bark or other cultivar characteristics.

Accepted botanical name

Acer palmatum

In the US and Canada

Introduced in Canada and the lower 48 states.

Native range

Japan and Korea.

Measured

Soil pH 6.5 to 7. Average height 700 cm.

Sources: GBIF (CC BY 4.0), USDA PLANTS and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.