Mountain Pine (Pinus mugo)

Mountain Pine, Dwarf Mountain Pine, Scrub Mountain Pine, Swiss Mountain Pine, Bog Pine, Creeping Pine, Mugo Pine

If you love the beauty and fragrance of pine trees but don’t want to commit to their towering heights, the Mugo pine tree is perfect for you. This carefree evergreen is short and shrubby in appearance. It has a slightly spreading and rounded dense habit of growth. 

I. Appearance and Characteristics 

Pinus mugo, known as dwarf mountain pine, mountain pine, scrub mountain pine, Swiss mountain pine, bog pine, creeping pine, or mugo pine, is a species of conifer.

Mugo pine (Pinus mugo) is a carefree evergreen that can take the place of overused landscape ground cover plants such as junipers. Short, shrubby varieties are neat in appearance with branches that grow to within inches of the soil. It has a naturally spreading habit and tolerates light shearing. In spring, new growth shoots almost straight up at the tips of the horizontal stems to form “candles.” Lighter in color than the older foliage, the candles form an attractive accent that rises above the shrub. Shearing off the candles results in dense growth the following season.

Pinus mugo is native to the subalpine zones of the Pyrenees, Alps, Ore Mountains, Carpathians, northern and central Apennines, and higher Balkan Peninsula mountains – Rila, Pirin, Korab, Accursed Mountains, etc. It is usually found from 1,000–2,200 m (3,281–7,218 ft), occasionally as low as 200 m (656 ft) in the north of the range in Germany and Poland, and as high as 2,700 m (8,858 ft) in the south of the range in Bulgaria and the Pyrenees. Also in Kosovo it is found in Bjeshkët e Nemuna National Park.

In Scandinavia, Finland and the Baltic region, P. mugo was introduced in the late 1700s and the 1800s, when it was planted in coastal regions for sand dune stabilization, and later as ornamental plants around residences. In Denmark, Norway and Sweden, the species has naturalised and become invasive, displacing fragile dune and dune heath habitats. In Estonia and Lithuania P. mugo only occasionally naturalises outside plantations, sometimes establishing in raised bogs.

Pinus mugo is classed as a wilding conifer, and spreads as an invasive species in the high country of New Zealand, coastal Denmark, and other areas of Scandinavia.

II. How to Grow and Care

Sunlight

While mugo pines will tolerate part shade at the northern end of their range (zones 2 to 5), in these regions you will see better performance if the shrubs are planted in full sun. Part shade might be preferable when growing them at the southern end of their range (zones 5 to 7).

Temperature and Humidity

Dwarf cultivars generally can survive in a wide climate range and can tolerate both hot summers and cold winters. They rarely suffer winter burn on the foliage from the drying winds of winter, as do arborvitae and some other evergreens.

Watering

For newly planted seedlings or new plants, water once every morning and evening during hot spells in the summer. Do not water midday, as this can cause root burn or strangle. Water plants according to your individual climate and rainfall in other seasons. For mature plants, only water when they are dry, keeping in mind that these plants are drought resistant. For indoor potted plants, spray water on the surfaces of the leaves once every morning and evening when it is dry. Be careful not to provide excess water – this hinders air circulation in a pot, leading to the rotting of roots and the withering of branches and leaves.

Soil

Mugo pines are not fussy about soil pH and can tolerate slightly acidic to slightly alkaline soil (pH 6.5 to 7.5). They are also tolerant of various soil types, provided it drains well; they do not like wet, dense soil.1 These shrubs do well in sandy soil, provided it has some organic matter in it.

Fertilizing

The mugo pine likes fertilizer and should be fertilized frequently, with just a small amount each time, during its growth period. It should be fertilized once a month in late spring, early summer, and fall. A fermented organic fertilizer is most effective for promoting growth.

Generally, do not apply a nitrogen fertilizer, such as urea or human urine, because pine needles already absorb nitrogen from the air, and pine roots are sensitive to nitrogen. You would be best off with a liquid fertilizer, applying this when the soil is dry in the afternoon. Water the plant again after fertilizer application, which will help with root absorption.

Do not use fertilizers that haven’t been fermented, or those with a higher concentration; the former will burn the roots and the latter will lead to the spindling of needles and more root damage, and could even cause the back-flow of sap, leading to water loss and the withering of the plant. No fertilizer should be applied in midsummer, during severe winters, or in the rainy season in the spring.

Generally, plants in gardens should be fertilized twice during the growth periods in spring and fall. Apply an organic fertilizer once before germination in the spring and apply slightly more fertilizer in the fall to promote robust growth. Stop fertilizing after midsummer so as to prevent spindling.

Planting Instructions

Mugo pine is best planted in early spring. Ideally, use healthy and vigorous seedlings with soil balls, as this can greatly improve the survival rate. In the case of many lateral roots, the deep main root can be cut. Otherwise, the root system should be protected to avoid damage.

plant in a high, dry, well-drained, and well-ventilated place, with loose soil. In low-lying places with accumulated water, or places with sticky soil, try building a platform or changing the soil before planting. The planting pit should be treated with a basal fertilizer before planting. Newly planted large seedlings should be supported to prevent them being blown down by the wind. 

Before planting, excess branches should be pruned off. Protect the plant’s shape from damage as much as possible, as this will help to restore growth at a later stage.

Ideally, plant indoor potted plants in the spring, and repot every two or three years in the late fall or early spring. Repotting too frequently will lead to the death of the plant. If the plant is growing weakly, find out the cause of this and change the flowerpot soil, or replant in a larger pot.

Cut back on water before repotting, so as to keep the soil slightly dry. Remove the soil ball from the pot, keeping it whole, and then prune away any old roots from the bottom and sides. Remove some of the old soil from the middle of the soil ball, replace with new soil, apply a small amount of basal fertilizer, and then cover the plant with new soil. Ensure a suitable pot size – a deep pot will easily accumulate water, leading to root rot.

Pruning

Home owners sometimes purchase and plant mugo pines under the false assumption that all cultivars are compact in size. The result of this uninformed plant selection is that homeowners end up with plants that are too big for the space in which they are growing. This drawback is somewhat offset by mugo pines’ slow growth rate.

If you find yourself with a mugo pine that is growing beyond the dwarf size you were expecting, you can shape the plant in spring by removing the central shoots of new growth (called “candles”). Pruning these central candles by half their length will create a more dense, compact plant.

Propagation

Mugo pine is best propagated from cuttings, as growing them from the seeds contained in the pine cones produces plants with a lot of variation in shape and size, and not true to cultivar type.

  • In May or June, when the needles have formed and they are still soft, using a sharp knife or pruners, cut off 5- to 7-inch long, strong stems from the new growth.
  • Remove any side shoots and the needles from the lower portion of the stems. None of the needles should be buried in soil so make sure to remove enough needles.
  • Fill 4-inch pots with potting mix. Dip the cut ends in rooting hormone. Make a hole in the soil with a pencil or stick and insert the cutting in the holes. Water well until the soil is evenly moist.
  • Place the pots in an outdoor location in bright, indirect light out of the hot sun. Keep the soil moist at all times but not soggy. It can take up to two months for the cuttings to root.
  • Repot any cuttings that have rooted to larger individual pots and let them grow in pots for a couple of seasons. The stronger they are when transplanted, the better their chance of survival in the landscape.

Overwintering

Unlike mugo pine planted in the ground, container plants need winter protection as the vulnerable roots are not insulated and exposed to temperatures below zero, which can kill them even though the plant is hardy down to USDA zone 2.

Once the temperature remains consistently below freezing, move the container to an unheated space such as a garage where the temperature remains consistently between 20 and 30 degrees F. Water regularly to keep the soil most until the air temperatures warm up again in the spring.

Pests and Diseases

Most dwarf mugo pines are virtually maintenance-free, barring any insect or disease problems, which are not common. Mugo pines are rarely infested with insects or plagued by diseases, but gardeners in some regions should watch out for pine sawfly and pine needle scale, as well as various moths and borers, tip blight, rots, and rusts.2

Insecticidal soaps are the first option for treating most insects, but you can progress to chemical pesticides if necessary. Fungicides applied in the spring can be used if your shrub suffers from a fungal disease.

III. Uses and Benefits 

  • Ornamental uses

Pinus mugo is widely cultivated as an ornamental plant, for use as a small tree or shrub, planted in gardens and in larger pots and planters. It is also used in Japanese garden style landscapes, and for larger bonsai specimens. In Kosovo, its trunk is used as construction material for the vernacular architecture in the mountains called “Bosonica”.

  • Culinary uses

A recent trend is the increase in use of the mugo pine in cooking. Buds and young cones are harvested from the wild in the spring and left to dry in the sun over the summer and into autumn. The cones and buds gradually drip syrup, which is then boiled down to a concentrate and combined with sugar to make pine syrup. The syrup is usually sold as “pinecone syrup” or “pine cone syrup”.

Mountain Pine (Pinus mugo) Details

Common name Mountain Pine, Dwarf Mountain Pine, Scrub Mountain Pine, Swiss Mountain Pine, Bog Pine, Creeping Pine, Mugo Pine
Botanical name Pinus mugo
Plant type Perennial
Hardiness zone 2a, 2b, 3a, 3b, 4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b
Growth rate Slow
Harvest time Fall
Height 20 ft. 0 in. - 25 ft. 0 in.
Width 20 ft. 0 in. - 25 ft. 0 in.
Sunlight Full sun (6 or more hours of direct sunlight a day)
Soil condition Loam (Silt)
Flower color Gold/Yellow
Leaf color Green