Red maple

Red maple: how do you recognise it?

Habit

Tree of 15–25 m, in gardens usually 10–15 m, with an oval to rounded crown.

Leaf

Opposite, 6–10 cm, with 3 (sometimes 5) shallow, irregularly toothed lobes; green above, blue-white below. Leaf stalk often red, without milky sap. Autumn colour fiery red, on some trees orange or yellow.

Bark

Smooth and silver-grey for a long time, later darker and split into long plates; twigs and buds red.

Flower

Clusters of small red flowers on the bare branches, as early as March.

Fruit

Small, red winged seeds at a sharp angle, ripe as early as May–June.

Difference from silver maple

Silver maple has a much more deeply cut leaf with a silvery-white underside, and turns yellow in autumn.

Difference from sweetgum

Sweetgum has a glossy, star-shaped leaf that is alternate, and spiky balls.

Flowering: March · Pruning: July–October

Identify by feature: Palmate leaves · Opposite leaves · White or silver underside · Red autumn colour · Winged seeds

Looks like it, but isn’t

• Silver maple Acer saccharinum: much more deeply cut leaf with a silvery-white underside; turns yellow in autumn. Difference from silver maple
• Sweetgum Liquidambar styraciflua: glossy, star-shaped leaf that is alternate, and spiky balls. Difference from sweetgum

Why grow it?

• Fiery red autumn colour, especially in cultivars such as ‘October Glory’ and ‘Red Sunset’.
• Small red flowers as early as March: an early source of pollen for bees.
• Copes with wet soil just as well as fairly dry soil, as long as it is acid.
• A medium-sized maple that needs far less space than sycamore or Norway maple.

Red maple: where does it grow best?

• Sun to partial shade; its autumn colour is best in full sun.
• Acid soil is a must: on chalky soil its leaves turn pale and yellow. Otherwise it copes with moist, wet and fairly dry soil.
• Allow a crown about 10 m wide: suitable for a large garden, a park or a street.
• Its roots are shallow and dense: the soil under the crown becomes dry and full of roots. Keep it away from patios, paths and borders.

Light

Sun or partial shade

Legal basis

Acid soil

Moisture

Dry to wet

Size

15 m tall, 10 m wide

Hardiness

Throughout Belgium, no protection needed

Goes well with

• Snowy mespilus: Another blaze of autumn colour on acid soil, with white blossom in April.
• Highbush blueberry: Needs the same acid soil and turns just as red in autumn.
• Rhododendron: Evergreen and acid-loving, for the partial shade at the edge of the crown.
• Witch hazel: Flowers in midwinter and turns yellow to orange in autumn, next to the red of the maple.

Good and bad companions

Goes well with

• Tolerate the shade under this tree: oregon grape, rhododendron, oleaster, japanese skimmia, garden privet, camellia, laurustinus, box-leaved honeysuckle

Red maple: when and how to plant it?

1. Plant from November to March, root-balled or container-grown.
2. Choose a spot with acid soil. On chalky soil, plant a different tree: a planting hole filled with acid soil is no lasting solution.
3. Put a stake on the windward side and water well after planting.
4. Buy a named cultivar if you want to be sure of bright red autumn colour: seedlings colour unpredictably, sometimes only yellow.

Care

Watering

In dry spells for the first two years; after that only during long droughts, especially on sandy soil.

Mulch

A layer of leaf mould or wood chips under the crown keeps the soil cool and moist.

Trunk

The bark is thin: keep mowers and strimmers away from the trunk, for example with a circle of mulch around the base.

Yellow leaves

Yellow leaves with green veins in summer point to soil that is too chalky. Iron fertiliser only helps for a while.

Tip: If you want to be sure of a bright red tree, choose it at the nursery in autumn: then you can see which tree colours best.

Red maple: when to prune it?

Pruning months: July–October.

When: In summer or early autumn (July–October). In spring it bleeds heavily.

How:

• Little pruning needed. Shape a young tree with a single central stem and wide branch angles.
• Remove dead, crossing and low-hanging branches; cut large branches in three stages, just outside the branch collar.

Caution: Don’t prune from late winter into spring: it bleeds heavily then. Never throw leafy prunings into a horse paddock.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Sowing

Sow the fresh seeds as soon as they ripen, in June: they often germinate the same summer. Seedlings vary in autumn colour.

Cultivars

Cultivars with reliable autumn colour are grafted or grown from cuttings by the nursery.

Red maple: how does it get through the winter?

Hardy throughout Belgium: no protection needed.

• Fully hardy.
• In winter you can recognise it by its red twigs and buds; the flower buds are already plump in February.

Diseases and pests

• Yellow leaves: On chalky soil it cannot take up iron: the leaves turn pale to yellow, with green veins, and the tree languishes. The only real cure is acid soil.
• Aphids and honeydew: Sticky drops under the tree in summer. A nuisance but harmless.
• Dry soil under the crown: Because of the shallow roots, little grows beneath the tree. Choose tough ground cover or mulch.
• Damaged trunk: Mowers and strimmers easily damage the thin bark. A circle of mulch around the base prevents this.

Through the year

• March: Flowering: small red flowers on the bare branches. Last month for planting.
• June: The red seeds ripen and fall: sow them straight away if you like.
• July: Summer pruning: the right time for maples. Water in dry spells.
• August: Pruning still possible; water during long droughts.
• September: Pruning still possible; the first leaves start to colour.
• October: Full autumn colour. Last month for pruning.
• November: Planting season begins; keep horses away from fallen leaves.

What can you use it for?

Garden and landscape

Garden and street tree with spectacular red autumn colour, especially in cultivars such as ‘October Glory’.

For wildlife

Flowers as early as March and is then an early source of pollen for bees.

Food and drink

The spring sap also yields maple syrup, though it is less sweet than that of sugar maple.

Caution: Wilted or dried leaves are poisonous to horses. Do not plant it near a horse paddock.

Did you know?

• One of the most widespread trees in North America. It needs acid soil: on chalk its leaves turn pale and yellow.
• In America it is also called ‘swamp maple’: it grows there in swamps as well as on dry hillsides.
• The spring sap also yields maple syrup, though it is less sweet than that of sugar maple.