Japanese white pine

Japanese white pine: how do you recognise it?

Habit

Slow, broad-growing conifer up to about 10 m tall and 6 m wide, with horizontal to rising branches and an irregular, open crown.

Needles

Five per bundle, 3–6 cm long, slender and slightly twisted; blue-green with white lines on the inner side.

Cones

Egg-shaped cones of about 5–7 cm, often in small groups along the branches.

Bark

Smooth and grey on young trees, later flaky and darker.

Roots

Deep-rooting and unhappy about being moved: put it in its final position straight away.

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

Why grow it?

• An elegant, slow-growing pine that fits a smaller garden and stays compact for a long time.
• Blue-green needles and a beautiful, horizontal branch structure give the garden shape all year.
• Evergreen: a reliable presence in the winter garden.
• Typical of Japanese and Asian gardens, gravel and rock gardens, and a classic bonsai subject.
• Little work: it needs hardly any pruning, only pinching the candles keeps it compact.

Japanese white pine: where does it grow best?

• Sun to half shade; for good, compact growth it needs at least half a day of sun.
• Well-drained sandy or loamy soil, acid to neutral; avoid chalky, heavy or waterlogged ground.
• Normal moisture; it dislikes wet feet. Mix coarse sand into heavy soil or plant on a slight mound.
• Sheltered from cold, drying winds. Allow 4–6 m of width for a mature tree; in a Japanese garden it can stand closer if you keep it small.

Light

Sun and partial shade

Soil type

Sand or loam

Acidity

Acid or neutral

Moisture

Normal

Size

10 m tall, 6 m wide

Hardiness

Hardy (to -25 °C)

Goes well with

• Japanese maple: Finely cut foliage and wonderful autumn colour, a classic in the Japanese garden.
• Japanese azalea: Flowers in May next to the pine and enjoys the same acid soil.
• Hakone grass: Arching, flowing leaves for the half shade under or beside the pine.
• Heather: A low, flowering ground cover for acid, sunny soil.

Japanese white pine: when and how to plant it?

Plant in April–May and September–October.

1. Plant in April–May or in September–October, preferably a container or rootballed plant. Never let the rootball dry out.
2. Dig a hole twice as wide as the rootball and just as deep. Loosen the sides so the roots can spread easily.
3. Set the pine at the same depth as in its pot, with the root collar level with the soil.
4. Backfill, firm lightly and give it a generous watering.
5. Spread a layer of pine bark or wood chips around the base, but not against the trunk.

Care

Water

In the first two summers, water generously once a week in dry weather. After that rain is enough, except in long dry spells.

Feeding

Hardly needed. On poor soil a little compost in spring is enough; avoid fertilisers high in nitrogen.

Mulching

A layer of pine bark or wood chips keeps the soil cool and moist. Keep it away from the trunk.

Pinching candles

In May, pinch or cut the young shoots (candles) back by half. This keeps the pine compact and dense.

Old needles

In autumn the oldest, innermost needles turn brown and fall: this is normal. Pull them off by hand for a tidier look.

Tip: Pinch the new candles back by half every spring: it stays compact for years and forms dense bundles of needles. Never cut into bare wood.

Japanese white pine: when to prune it?

Pruning months: May.

When: Only in May, while the young shoots (candles) are still soft and the needles have not yet opened.

How:

• Pinch or cut the new candles back by about half with sharp scissors, before the needles unfurl.
• Do this every year: it keeps the crown dense and compact.
• Cut dead, crossing or damaged branches back to the trunk.

Caution: Never cut into bare, brown wood without needles or buds: a pine will not sprout again from it. Always leave some green.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Seed

The seed needs a cold period: sow in autumn in a tray outdoors, or keep it moist in the fridge for a few weeks and sow in March. Garden forms do not come true from seed, and growth is slow.

Grafting

Garden forms are grafted by nurseries, often onto another pine. This is difficult for the home gardener: buy a plant instead.

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

Hardy to −25 °C.

• Hardy to about −25 °C: no protection is needed in Flanders.
• Heavy, wet snow can break branches: shake it gently off.
• In a pot: put it in a sheltered spot, wrap the pot in hessian or bubble wrap and water occasionally in dry, frost-free weather.

Diseases and pests

• Woolly aphids: White, woolly patches on shoots and needles. Wash them off with a strong jet of water or dab them with soapy water; they often disappear by themselves.
• White pine blister rust: Orange blisters or swellings on the branches of five-needle pines, with dying tips above. Cut affected branches well back into healthy wood and dispose of them.
• Wet feet: Needles turn yellow or brown and growth stalls. Provide free-draining soil or plant on a mound.
• Brown needles: Only the oldest needles turn brown and drop in autumn: that is normal. If young needles change colour, think of drought, winter wind or root damage.

Through the year

• April: Plant. Apply mulch.
• May: Plant. Pinch the young candles back by half.
• June: Water young trees in dry weather.
• July: Water young specimens. Watch for woolly aphids.
• August: Water during prolonged drought.
• September: Plant. Water regularly after planting.
• October: Plant. Remove old, brown needles.
• November: Clear fallen needles. Protect pots from frost.
• December: Rest. Shake heavy snow off the branches.

Did you know?

• In Japan this pine is called goyomatsu, ‘five-needle pine’. It is one of the classic bonsai species.
• Garden forms are often grafted onto the roots of another pine, usually the Japanese black pine.
• The number of needles per bundle is a handy clue: this pine has five, while Scots pine and maritime pine have two.