Mountain pine

Mountain pine: how do you recognise it?

Habit

Broad, shrubby pine with several stems, up to 3 m tall and as wide; dwarf cultivars stay at 0.5–1.5 m.

Needles

In pairs, 3–8 cm long, stiff, often slightly curved and dark green. They stay on the branch for several years.

Cones

Small and egg-shaped, 2–5 cm long, purplish at first and later brown. They only ripen in their second year.

Candles

In spring, upright new shoots, the ‘candles’, on which the new needles later develop.

Roots

Widely branched and deep enough to cope with drought. Preferably move it while it is still young.

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

Why grow it?

• Green all year round: permanent structure in a rock garden, heather garden or gravel border.
• Extremely hardy and wind-resistant, even on an open, exposed site.
• Drought-tolerant once established: suitable for poor sandy soil and gravel gardens.
• Grows on acid, neutral and chalky soil, which not every conifer can do.
• By shortening the candles in May you can keep it compact for years; dwarf cultivars even fit in a pot or trough.

Mountain pine: where does it grow best?

• Full sun: in shade it becomes sparse and bare in the centre.
• Any well-drained soil: sand, loam or clay, acid, neutral or chalky.
• Dry to moderately moist; on heavy clay make sure drainage is good.
• An open, windy spot is no problem: it comes from high mountains.
• Allow 2.5–3 m of space for the species and 1–1.5 m for dwarf cultivars. Check the label for the size of your cultivar.

Light

Sun

Soil type

Sand, loam or clay

Acidity

Not fussy

Moisture

Dry or normal

Size

3 m tall, 3 m wide

Hardiness

Hardy (to -40 °C)

Goes well with

• Winter heath: Flowers in winter in pink and white and, like mountain pine, tolerates some lime.
• Lavender: Silver-grey leaves and purple flowers in the same dry, sunny spot.
• Blue fescue: A blue tuft of grass that contrasts with the dark green needles.
• Thyme: A low, fragrant mat between the stones of the rock garden.
• Stonecrop: Drought-tolerant and colourful in late summer, ideal in a gravel garden.

Mountain pine: when and how to plant it?

Plant in March–April and September–October.

1. Plant in March–April or September–October, when the soil is neither frozen nor waterlogged.
2. Dig a hole twice as wide as the root ball; on heavy soil loosen the bottom and mix in some coarse sand or gravel.
3. Set the plant at the same depth as it was in the pot or root ball: the base of the trunk must not be buried.
4. If the root ball is wrapped in hessian, leave it on but loosen it at the top around the trunk.
5. Firm the soil well and water thoroughly straight away.
6. A layer of bark or gravel around the base keeps weeds down and the soil moist.

Care

Water

In the first year, water regularly in dry weather, including a dry spring. After that, in open ground it rarely needs extra water.

Feeding

Usually unnecessary. On very poor sandy soil a spadeful of compost in spring is enough.

Candles

Snapping the new candles in half at the end of May keeps it compact and dense.

In a pot

Use a large pot with a drainage hole and a free-draining mix of potting compost and grit. Water regularly in summer: a pot dries out quickly.

Needle drop

In autumn the oldest needles on the inside turn yellow and fall. That is normal.

Tip: Buy a true dwarf cultivar if space is limited: an ordinary seedling can eventually grow 3 m wide. Snap the candles with your fingers, not with secateurs.

Mountain pine: when to prune it?

Pruning months: May.

When: At the end of May, when the new candles are fully extended but the needles have not yet opened out.

How:

• Snap the candles back by half or by a third. Using your fingers avoids cut needle tips that turn brown.
• Do this every year: the pine stays compact and becomes denser.
• Dead or damaged branches can be removed at any time of year, back to a healthy side branch or to the trunk.
• To shorten a branch, cut just above a side branch that still has needles.

Caution: Never cut back into bare wood without needles: a pine does not form new buds there and the branch stays bare.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Seed

Pick ripe, still closed cones in late winter and let them open in a warm place. Sow in spring in pots and cover the seed lightly. Seedlings often vary a lot in shape and size.

Grafting

Cultivars such as the dwarf forms are grafted onto a rootstock by nurseries. Cuttings rarely root in pines, so it is better to buy named cultivars.

Mountain pine: how does it get through the winter?

Hardy to −40 °C.

• Fully hardy, to about −40 °C: in Belgium it never needs protection.
• Shake heavy, wet snow off the branches so that they do not splay out or break.
• In a pot: stand it against a wall and water now and then on frost-free days, so that the needles do not dry out.

Diseases and pests

• Pine sawfly: In May–June, groups of grey-green larvae with black heads eating last year’s needles. When disturbed, they rear up together. Shake or snip them off into a bucket.
• Red band needle blight: Needles with red to brown bands that die off from the bottom of the shrub upwards. Rake up fallen needles, cut out badly affected branches and choose an airy site.
• Pine woolly aphid: White, woolly tufts on the branches and young shoots. Usually harmless: brush them off or blast them with a strong jet of water.
• Brown needles: On a young plant usually drought or soil that is too wet and poorly drained. Water in dry weather and make sure drainage is good.

Through the year

• March: Plant. Give a little compost on poor soil.
• April: Plant. Water young plants in a dry spring.
• May: At the end of May, snap the candles in half. Watch for sawfly larvae.
• June: Shake off sawfly larvae. Water young plants in dry weather.
• July: Water plants in pots regularly.
• September: Plant or move.
• October: Plant. Old yellow needles on the inside drop: that is normal.
• December: Shake heavy snow off the branches.

Did you know?

• In the Alps, mountain pine grows above the tree line as dense, creeping scrub that holds the soil on steep slopes.
• Pine cones take about eighteen months to ripen, so young and ripe cones often hang on the shrub at the same time.
• Mountain pine was once widely planted to fix drifting sand in the dunes of Denmark and the Netherlands.