Dwarf birch

Dwarf birch: how do you recognise it?

Habit

Low, broad, densely branched shrub 0.5–1 m high and wide; often creeping in the wild.

Leaves

Almost round, 0.5–2 cm, with a scalloped margin; glossy dark green, yellow to orange-red in autumn. Deciduous.

Flowers

Small, inconspicuous catkins in April–May, male and female on the same plant; wind-pollinated.

Twigs

Thin, reddish-brown and slightly hairy.

Roots

Shallow and finely branched: they dry out quickly in summer.

Plants: March–April and October–November · Pruning: November–December

Why grow it?

• A pocket-sized birch: it fits the smallest garden, a rockery or a large container.
• Neat, round leaves and lovely autumn colours in yellow, orange and red.
• Extremely hardy: frost is never a problem.
• A natural partner for heathers, bog plants and other plants of acid, moist soil.
• Thin, reddish-brown twigs give a fine outline in winter too.

Dwarf birch: where does it grow best?

• Sun or partial shade; inland, ideally a spot with some afternoon shade.
• Acid soil: sand or peat, poor and humus-rich. It will not tolerate chalk.
• Moist to wet: drying out is its worst enemy. A pond edge or a damp heather garden is ideal.
• Cool and airy: it dislikes a hot spot against a wall or on a stone patio.
• Allow 0.8–1 m per plant.

Light

Sun and partial shade

Soil type

Sand or peat

Acidity

Acid

Moisture

Normal or wet

Size

1 m tall, 1 m wide

Hardiness

Hardy (to -40 °C)

Goes well with

• Heather: Flowers in late summer in the same acid, poor soil.
• Cross-leaved heath: Like dwarf birch, it loves moist, acid soil.
• Lingonberry: A creeping evergreen with red berries at the foot of the shrub.
• Cottongrass: White tufts in a wet spot of the heather garden.
• Purple moor grass: An airy grass of damp heaths, turning golden in autumn.

Dwarf birch: when and how to plant it?

Plant in March–April and October–November.

1. Plant in March–April or October–November, when the soil is not frozen.
2. Dig a hole twice as wide as the root ball. If your soil is not acid enough, mix in ericaceous compost or composted pine needles.
3. Set the plant at the same depth as in the pot and firm the soil well.
4. Water generously, preferably with rainwater: tap water is often limy.
5. Mulch with pine needles, bark or leaf mould to keep the soil cool and moist.

Care

Water

Keep the soil moist at all times, especially in warm summers. Use rainwater where possible.

Feeding

Hardly needed. At most a thin layer of leaf mould or a little ericaceous fertiliser in April.

Mulching

A layer of pine needles or bark keeps the roots cool and the soil acid.

In a pot

Can be grown in a large pot of ericaceous compost. Stand it in partial shade and never let it dry out.

Tip: Give it a cool spot with moist, acid soil, for example on the north side of a heather garden or by a pond, and water with rainwater: it will stay fresh even in warm summers.

Dwarf birch: when to prune it?

Pruning months: November–December.

When: Pruning is rarely needed. Remove dead or crossing shoots in November–December, after leaf fall.

How:

• Cut out dead, damaged or crossing twigs back to healthy wood or to the base.
• Keep the natural, slightly irregular shape as far as possible.
• If the shrub gets too wide, shorten a few of the longest shoots to a side branch.

Caution: Do not prune in late winter or spring: birches ‘bleed’ heavily from pruning cuts at that time.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Layering

In spring, bend a low branch to the ground and peg it down; shoots touching the soil sometimes root by themselves. Sever after a year and transplant.

Seed

Sow fresh seed in autumn on acid, moist seed compost and do not cover it: birch seed needs light to germinate. Leave the tray outdoors over winter.

Dwarf birch: how does it get through the winter?

Hardy to −40 °C.

• Extremely hardy, to about −40 °C: no protection is ever needed in Belgium.
• Even in a pot it can stay outdoors all winter.
• Its weak point is not cold but summer heat: make sure the soil stays cool and moist in summer.

Diseases and pests

• Drying out: Brown leaf edges and early leaf fall in hot, dry summers. Water with rainwater, mulch and find a cooler spot.
• Yellow leaves: Yellow leaves with green veins point to chalky soil. Move it into acid soil and water with rainwater.
• Aphids: On young shoots in spring. Natural predators usually deal with them; otherwise hose them off.
• Birch rust: Orange pustules under the leaves in late summer. Usually harmless: clear up fallen leaves.

Through the year

• March: Plant. Top up the mulch.
• April: Plant. New leaves and small catkins.
• May: Watch for aphids. Check the mulch.
• June: Water in dry weather, preferably with rainwater.
• July: Keep the soil cool and moist.
• August: Water in hot weather.
• October: Plant. Yellow to orange-red autumn colour. Sow seed.
• November: Plant. Remove dead or crossing twigs.
• December: Dormant. Light pruning if needed.

Did you know?

• In the tundra, dwarf birch is often only a few tens of centimetres tall and creeps along the ground, protected under the snow.
• During the last ice age dwarf birch also grew in the Low Countries; its pollen and leaves have been found in ancient soil layers.
• In the wild it hybridises readily with downy birch.