Bhutan pine

Bhutan pine: how do you recognise it?

Habit

Broad, conical tree 20–25 m tall and 10–12 m wide, with an open crown and drooping needles.

Needles

Five per bundle, 12–20 cm long, flexible and hanging, blue-green with white lines on the inner side.

Cones

Long, slender, often curved cones of 15–30 cm, hanging and resinous.

Bark

Smooth and grey-brown when young, later cracking into small plates and darkening.

Roots

A deep root system; it transplants best when young.

Plants: April–May and September–October

Why grow it?

• Soft, hanging, blue-green needles give the tree a graceful, almost weeping look.
• Large, curved, resinous cones of 15–30 cm catch the eye in autumn.
• Fully hardy in Flanders, to about −25 °C.
• Evergreen: structure and shelter for birds all year.
• A fine specimen for large gardens and parks, with an open, elegant crown.

Bhutan pine: where does it grow best?

• Full sun; it tolerates a little light half shade but grows best in sun.
• Well-drained sandy or loamy soil, acid to neutral; no wet or very chalky ground.
• Normal moisture; it tolerates temporary drought once established.
• Sheltered from cold, drying wind. Allow 8–12 m of free space; do not plant it close to houses or boundaries.

Light

Sun

Soil type

Sand or loam

Acidity

Acid or neutral

Moisture

Normal

Size

25 m tall, 12 m wide

Hardiness

Hardy (to -25 °C)

Goes well with

• Birch: Light foliage and white trunks make a lovely contrast with the blue-green pine.
• Rhododendron: An evergreen underplanting that flowers in May and likes acid soil.
• Ferns: Fresh, green underplanting in the half shade at the foot of the tree.
• Ornamental grasses: Soft tufts that echo the long, flexible needles.

Bhutan 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 young container or rootballed tree. Do not let the rootball dry out.
2. Dig a hole twice as wide as the rootball and just as deep. Loosen the sides with the spade.
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 wood chips or pine bark around the base, not against the trunk.

Care

Water

In the first two summers, water generously once a week in dry weather. After that it manages on rain.

Feeding

Usually not needed. On very poor soil a little compost in spring is enough.

Mulching

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

Needles and cones

In autumn old needles fall and the cones open: sweep them up or leave them as natural mulch.

Protect young trees

In the first winters, put a windbreak of hessian or brushwood on the cold side and protect the trunk from mowers.

Tip: Give it a roomy, sunny spot sheltered from cold wind. Shake young trees clear after heavy, wet snow, because the long needles hold it.

Bhutan pine: when to prune it?

When: It normally needs no pruning. Dead or damaged branches can be removed from winter to early spring.

How:

• Cut dead, broken or crossing branches back to the trunk.
• Always keep one continuous leader: never cut off the top.
• To raise the lower crown, remove low branches while they are still thin.

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

Pruning calendar and basic rules

Propagation

Seed

Sow in autumn in a tray outdoors, or keep the seed moist in the fridge for a few weeks and sow in spring. Seedlings grow slowly at first.

Buying

Nurseries raise the species from seed. A young plant of 1–1.5 m settles in most easily.

Bhutan pine: how does it get through the winter?

Hardy to −25 °C.

• Hardy to about −25 °C: no protection is needed for mature trees in Flanders.
• The long, soft needles hold wet snow: gently shake young trees clear after heavy snowfall.
• Put young trees where they are sheltered from cold, drying east winds.

Diseases and pests

• Branch breakage: Heavy, wet snow or a storm can break branches. Shake young trees clear and cut broken branches cleanly back to the trunk.
• Winter wind: Needle tips turn brown from cold, drying wind. Choose a sheltered spot and water in frost-free weather.
• Woolly aphids: White, woolly patches on shoots and needles. Wash them off with a jet of water or dab them with soapy water.
• 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.

Through the year

• March: Remove dead or damaged branches. Planting is possible from late March.
• April: Plant. Apply mulch.
• May: Plant. Water young trees in dry weather.
• 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. The cones ripen.
• November: Clear fallen needles. Put up a windbreak for young trees.
• December: Rest. Shake heavy snow off the branches.

Did you know?

• The species name honours Nathaniel Wallich, the Danish botanist who ran the botanic garden in Calcutta.
• It is also called the ‘blue pine’ because of its blue-green needles.
• In the Himalaya it grows at altitude, well above 2,000 m.