Japanese red pine

Japanese red pine: how do you recognise it?

Habit

Evergreen tree about 15 m tall and 8 m wide, with an irregular, often leaning crown that flattens with age. ‘Umbraculifera’ stays much lower and grows umbrella-shaped.

Needles

Two per bundle, 8–12 cm, slender, soft and bright green.

Bark

Orange-red and flaking in thin plates on the upper trunk and branches; grey-brown and fissured lower down.

Cones

Small, egg-shaped, 3–5 cm, brown.

Roots

A strong root system: move it while young and plant it in its final position.

Plants: April–May and September–October · Pruning: May–June

Why grow it?

• Orange-red, flaking bark that glows in low sun.
• Soft, bright green needles in pairs.
• Graceful, often leaning growth: a living sculpture, ideal in a Japanese garden.
• Its growth can be steered by pinching the shoots in spring, so that it stays compact.
• Evergreen and fully hardy, to about −30 °C.

Japanese red pine: where does it grow best?

• Full sun: in shade it becomes thin and loses its attractive shape.
• Acid to neutral, well-drained soil: sand or loam. No heavy, waterlogged clay.
• Normally moist; no wet feet and no long drought.
• An open, airy spot, preferably sheltered from strong, cold wind.
• Allow 8 m width; for ‘Umbraculifera’ 2–4 m.

Light

Sun

Soil type

Sand or loam

Acidity

Acid or neutral

Moisture

Normal

Size

15 m tall, 8 m wide

Hardiness

Hardy (to -30 °C)

Goes well with

• Japanese maple: Graceful leaves and autumn colour beside the red bark, in the same spirit.
• Japanese azalea: Flowers in spring on the same acid to neutral, well-drained soil.
• Heather: Low, colourful planting beneath the crown.
• Japanese blood grass: A red grass that stands out beautifully against the orange-red bark.

Japanese red pine: when and how to plant it?

Plant in April–May and September–October.

1. Plant in April–May or in September–October, when the soil is neither frozen nor waterlogged.
2. Dig a hole twice as wide as the root ball and just as deep. Loosen the sides so the roots can grow out easily.
3. Set the plant at the same depth as in its pot or root ball: the root collar stays at soil level.
4. Give it 6–8 m from buildings and other trees, or choose ‘Umbraculifera’ where space is limited.
5. Water generously straight away, even if it is raining.
6. Spread a layer of bark or leaf mould mulch around the base, keeping it clear of the trunk.

Care

Water

For the first two years, water generously every week in dry spells. After that it usually manages on its own.

Feeding

Usually not needed. On poor soil, give a thin layer of compost in spring.

Mulching

Bark or leaf mould keeps the soil cool and moist, but keep it clear of the trunk.

Candle pinching

Pinching the young shoots in May–June keeps the crown compact and dense (see Pruning).

Checking

In spring, look for brown, crooked shoots; in summer, for aphids.

Tip: Pinch the candles every spring to keep the crown compact and dense. Give it sun and well-drained soil; on wet clay it declines.

Japanese red pine: when to prune it?

Pruning months: May–June.

When: It does not need pruning, but its growth can be steered: in May–June, pinch the young shoots (the ‘candles’) when they have lengthened but the needles are still pressed against the shoot.

How:

• Break or cut off half to two thirds of each candle, with your fingers or a sharp knife; the tree stays more compact and dense.
• Remove dead and damaged branches back to the trunk or a side branch.
• If you want to show off the attractive bark, gradually remove the lowest branches.
• Remove a double leader and leave one strong leader.

Caution: Never cut into bare wood without needles: a pine will not regrow from it.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Seed

For the species: collect the cones in autumn, let them dry and shake out the seeds. Sow them in spring in pots outdoors, after a cold period over winter.

Grafting

Selections such as ‘Umbraculifera’ are grafted by nurseries; seedlings do not come true to the parent plant.

Japanese red pine: how does it get through the winter?

Hardy to −30 °C.

• Fully hardy, to about −30 °C: no protection is needed.
• Gently shake heavy, wet snow off the branches so they do not break.
• In a pot: put the pot in a sheltered spot and wrap it in hessian so the roots do not freeze. Water in dry, frost-free weather.

Diseases and pests

• Shoot dieback: New shoots turn brown and bend in spring, with brown needles staying on. Cut affected shoots back into healthy wood in dry weather and avoid drought stress.
• Aphids: Grey or black aphids on needles and young shoots, sometimes with sticky honeydew. Spray them off with a strong jet of water; ladybirds help.
• Needle drop: Old needles turn yellow or brown after a few years and fall in autumn. This is normal; only worry if branches go bare or many needles die on the outside.
• Wet feet: Yellow needles and poor growth in heavy, wet or compacted soil. Choose a well-drained spot.

Through the year

• March: Check for winter damage. Renew the mulch.
• April: Plant. New candles appear. Watch for brown shoots.
• May: Plant. Pinch the candles. Apply mulch.
• June: Pinch the candles. Water young trees in dry weather.
• July: Water young trees in dry weather. Watch for aphids.
• August: Water in hot, dry weather.
• September: Plant. The cones turn brown.
• October: Plant. Needle drop is normal. Water new plantings.
• November: Move pots to a sheltered spot or wrap them against frost.
• December: Rest. Shake heavy snow off the branches.

Did you know?

• In Japan it is called akamatsu, ‘red pine’, after the orange-red bark.
• In Japan it has been pruned into cloud-shaped crowns (niwaki) for centuries and is a much-used bonsai tree.
• Its needles are softer than those of its relative the Japanese black pine (Pinus thunbergii), which has stiff needles and dark bark.