Norway maple

Norway maple: how do you recognise it?

Habit

Tree of 20–30 m with a dense, rounded crown.

Leaf

Opposite, 10–18 cm, with 5–7 lobes ending in long, pointed teeth; glossy. Snap the leaf stalk and white milky sap comes out.

Bark

Grey, finely and regularly fissured, does not flake.

Flower

Yellow-green flower clusters before the leaves open (April).

Fruit

Winged fruits with wings at a wide, obtuse angle.

Difference from sycamore

Sycamore has coarsely toothed lobes without long points, and no milky sap.

Difference from London plane

London plane has alternate leaves and bark that peels off.

Flowering: April · Pruning: July–October

Identify by feature: Palmate leaves · Opposite leaves · Yellow flowers in spring · Winged seeds

Looks like it, but isn’t

• Sycamore Acer pseudoplatanus: coarsely toothed lobes without long points, no milky sap. Difference from sycamore
• London plane Platanus × hispanica: leaves are alternate and the bark peels off. Difference from London plane

Why grow it?

• Early yellow-green flowers in April, before the leaves: important for bees.
• Yellow to orange autumn colour.
• Tough and easy: grows on almost any soil and tolerates urban conditions.
• There is a form for every spot, from the red-leaved ‘Crimson King’ to the small mophead ‘Globosum’.

Norway maple: where does it grow best?

• Sun to partial shade.
• Almost any soil, chalky ones included; copes well with urban conditions.
• Dense shade and shallow roots: little grows under the crown.
• Allow for a crown 14 m wide: the species suits a park, an avenue or a large garden; the mophead ‘Globosum’ stays small enough for an ordinary garden.

Light

Sun or partial shade

Legal basis

Any garden soil

Moisture

Normal

Size

25 m tall, 14 m wide

Hardiness

Throughout Belgium, no protection needed

Goes well with

• Common ivy: An evergreen ground cover that copes with the dense, dry shade under the crown.
• Lesser periwinkle: Flowers blue in spring and covers the ground in shade.
• Snowdrop: Flowers in February, long before the crown closes.
• Holly: Evergreen and shade-tolerant: green in winter under a bare crown.

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

Best kept away from

• Sun-loving plants get too little light under the dense crown: english lavender, heather, butterfly bush, blackthorn, highbush blueberry, sea buckthorn, japanese rose, broom

Norway maple: when and how to plant it?

1. Plant from November to March, bare-root or with a root ball.
2. Keep it well away from the house, patio and driveway: the roots run near the surface.
3. Put a stake on the windward side and tie the trunk loosely; remove stake and tie after 2–3 years.
4. Water generously after planting and during dry spells in the first year.

Care

Watering

In dry spells during the first and second year.

Feeding

Not needed; leave the fallen leaves under shrubs, where they turn into humus.

Seedlings

It seeds itself readily: weed out unwanted seedlings while they are young.

Under the tree

Lawn struggles in the dense shade; choose shade plants or a layer of mulch.

Tip: For a small garden or a front garden, choose the mophead maple ‘Globosum’: it stays compact and forms a round, dense crown.

Norway maple: when to prune it?

Pruning months: July–October.

When: In summer or early autumn (July–October), not in spring.

How:

• Prune mainly while young to form a good crown.
• A street tree can be crown-lifted: remove the lowest branches gradually.
• On the grafted mophead ‘Globosum’, remove shoots on the trunk, below the crown, straight away.

Caution: Don’t prune in late winter or spring: a maple bleeds heavily then.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Sowing

Sow the winged fruits outdoors in autumn; they germinate in spring.

Grafting

Red-leaved forms and the mophead don’t come true from seed: they are grafted by the nursery.

Norway maple: how does it get through the winter?

Hardy throughout Belgium: no protection needed.

• Fully hardy.
• In winter you recognise it by its grey, finely and regularly fissured bark that doesn’t flake.

Diseases and pests

• Tar spot: Large black spots on the leaves in late summer. Harmless to the tree; rake up the leaves in autumn.
• Aphids and honeydew: Sticky drops on cars and the patio under the tree in summer. A nuisance but harmless; tits and ladybirds help.
• Verticillium wilt: Branches or parts of the crown suddenly wilt in summer; the wood shows green streaks. Cut out affected branches and disinfect your saw; replace a badly affected tree.
• Seedlings: Young maples everywhere in borders and hedges. Pull them up while young.

Through the year

• March: Last month for planting.
• April: Yellow-green flowers before the leaves: food for bees.
• June: Watch for aphids and honeydew.
• July: Summer pruning: the right time for maples.
• August: Summer pruning; tar spots on the leaves.
• September: Pruning still possible; the winged fruits ripen.
• October: Yellow to orange autumn colour; last month for pruning.
• November: Planting season starts; clear up leaves with tar spot.

What can you use it for?

Garden and landscape

Widely used street and park tree, also with red leaves.

For wildlife

Flowers early, when it is important for bees.

Wood

Wood for furniture and turning.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Hoverflies

Open flowers for hoverflies; many of their larvae eat aphids.

Did you know?

• Widely planted as a street tree, also with dark red leaves (‘Crimson King’).
• The name platanoides means ‘like a plane tree’, after the shape of the leaf.
• In North America it has been planted so widely that it has become invasive in woodland there.
• Despite its name it grows naturally across much of Europe, from Scandinavia to the Caucasus. Platanoides means ‘plane-like’, after the shape of the leaf.
• In eastern North America, where it was widely planted as a street tree, Norway maple has become an invasive species that spreads into woodland.