The mugo pine (Pinus mugo) is a species of coniferous needled evergreen that is a favorite in landscape use. Many cultivars have been developed, most with a broad, spreading form, growing wider than they are tall. Several excellent small varieties are available, including 'Mops', a true dwarf that remains quite short, unlike some other so-called dwarf cultivars that grow relatively tall. 'Mops' and a few other cultivars are shrubs that are especially well suited for restricted spaces in the landscape where few pines are suitable.
Mugo pines are genetic descendants of much taller evergreen trees native to mountainous regions in Europe, a fact that gives you a clue to their hardiness. Many dwarf mugo pines are hardy to USDA zone 2, and they do not do well in areas with overly hot summers.
As with many shrubs, spring is a traditional planting time, as this gives the plant plenty of time to settle in and develop new roots before the winter cold arrives. However, the mugo pine can also be planted in the early fall, provided you give it enough time before first frost to settle in. Avoid planting in in the heat of mid-summer, if possible, though this tough shrub probably will survive no matter when you plant it.
A dwarf mugo pine is a slow-growing shrub that can take up to 10 years to achieve its mature size. This allows you to plant it in tight spaces without needing to prune it too often. Another selling point is that they are deer-resistant.
|Botanical Name||Pinus mugo cultivars|
|Common Names||Mugo pine, Swiss mountain pine|
|Plant Type||Needled evergreen shrub|
|Mature Size||Depends on cultivar; usually 2 to 5 feet tall; 3 to 5 foot spread|
|Sun Exposure||Full sun to part shade|
|Soil Type||Any well-drained soil|
|Soil pH||6.5 to 7.5 (slightly acidic to slightly alkaline)|
|Hardiness Zones||2 to 7 (USDA)|
|Native Areas||Central Europe, Balkans|
How to Grow Dwarf Mugo Pine
Dwarf mugo pines usually grow well in almost any soil other than dense clay. This plant prefers relatively cool conditions and has a good tolerance for urban environments. Growers usually recommend digging a large planting hole, amending the removed soil, if necessary, with small gravel (if the soil is clay) or peat moss (if the soil is sandy).
Remove the plant from its nursery container, gently loosen the roots, then position the shrub in the hole and pack the amended soil around the root ball. Tamp the soil as you go to remove air pockets, then water thoroughly.
Mugo pines have roots that grow close to the surface, so it is a good idea to mulch around the base to help keep the roots cool, especially in climates with hot summers.
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).
Mugo pine trees are not fussy about soil pH and can tolerate slightly acidic to slightly alkaline soil. They are also tolerant of various soil types, provided it drains well; they do not like wet, dense soil. These shrubs do well in sandy soil, provided it has some organic matter in it.
While your mugo pine is young, water as needed throughout summer so that the ground never dries out completely. Once established, mature shrubs are moderately drought-tolerant and need less frequent watering.
Temperature and Humidity
Dwarf cultivars generally can survive 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.
Fertilize your mugo annually with compost or another organic soil amendment. They typically do not need applied fertilizers, though a spring application might benefit those grown in containers.
Pruning Mugo Pine Trees
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.
Growing Mugo Pines in Containers
Small mugo pines grow well in containers and can be left outdoors all winter in most climates. Here are some of the smallest cultivars:
- 'Paul's Dwarf' grows to 2 to 3 feet tall and wide in 10 years; it has short needles and is hardy in USDA Zones 2 through 7.
- 'Honeycomb' grows to 4 feet tall in 10 years; its needles turn gold in winter. It is hardy in USDA Zones 3 through 5.
- 'Gnome': grows to 4 feet tall in 10 years, but is relatively wide at 5 feet. It is hardy in USDA Zones 3 through 7.
When growing mugo pines in containers, it's important to water them weekly during the growing season. As winter approaches, keep them well watered until the soil freezes. You can then stop watering if the soil remains frozen. Once the soil thaws in spring, or during warm spells in winter, water as soon as possible. Return to the regular watering schedule once the temperature rises for the season.
Container plants should be fed once in the spring, using a slow-release fertilizer.
Common Pests/ 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.
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.
Dwarf Varieties of Mugo Pine
- Pinus mugo 'Compacta' has dark green needles on dense branches and grows three to four feet tall and two to four feet wide. It is hardy in USDA zones 2 through 8.
- P. mugo 'Sherwood Compact' is a true dwarf that is densely needled with a rounded, shape. It is slow-growing and matures at two feet tall and wide. It is hardy in USDA Zones 2 through 7.
- P. mugo 'Enci' grows 3 feet tall and 5 feet wide. It is a dense, slow-growing shrub with short needles. It is hardy in USDA Zones 2 through 7.
- P. mugo 'Gnome' is a small, flat-top form. It grows slowly, topping out at only 18 to 24 inches tall and 3 feet wide. It is hardy in USDA Zones 3 through 7
- P. mugo 'Mops' has an especially dense growth habit that works well in confined spaces. It grows slowly to about four feet tall and two to three feet wide, taking 30 years to do so. It is hardy in USDA Zones 2 to 7.
'Mops' and other short mugo pines can function effectively as a low hedge or ground cover as well as foundation plantings or as evergreens for rock gardens. They can also be used as specimen plants in a mixed border. Some cultivars are used as bonsai specimens.
Pinus mugo 'Paul's Dwarf'. Missouri Botanical Garden
Steiner, Lynn M. Black & Decker The Complete Guide to Upper Midwest Gardening. Cool Springs Press, 2012