Plant Taxonomy of Mugo Pines:
Plant taxonomy classifies mugo pines as Pinus mugo. 'Mops' is an example of a dwarf cultivar, not to be confused with 'Gold Mops' false cypress. Unfortunately, the unreliable pumilio variety is more widely available than Mops.
Characteristics of Mugo Pine Trees:
Mugo pine trees come in a number of cultivars or varieties, and their plant form can vary from pyramidal to broadly spreading. As alluded to above, characteristics will depend on the cultivar or variety that you plant. When buying mugo pines, most consumers have in mind a dwarf tree: a plant 3-5 feet tall and broadly spreading (10 feet wide), that can function as a low hedge or groundcover. Such consumers may well end up disappointed if they bring home the pumilio variety, whose dimensions at maturity vary greatly, from instance to instance. For a true dwarf mugo pine, buy the Mops cultivar.
USDA Plant Hardiness Zones for Mugo Pine Trees:
Mugo pine trees can be grown in zones 3-7.
Sun and Soil Requirements for Mugo Pine Trees:
Mugo pine trees can be grown in partial shade to full sun. They're not fussy about pH but do demand a well-drained soil.
Uses for Dwarf Types:
In addition to their use as groundcovers and low hedges, dwarf mugo pine trees are used in foundation plantings and for rock gardens. They are drought tolerant trees; this, combined with their tolerance of partial shade, makes them adaptable and helps account for how popular these plants are.
Pruning Mugo Pine Trees:
As mentioned above, people sometimes plant mugo pine trees under the false assumption that they're all dwarfs and end up with plants too big for the space in which they're growing. This drawback is somewhat offset by mugo pines' slow growth rate. But if you find yourself stuck with pumilio mugo pine trees that are growing beyond the dwarf size you had been expecting, you can step in and shape the plants to some degree, through partial removal of the new candles in spring; this will slow the growth rate further.
Other Care for Mugo Pines:
If you're growing a cultivar such as Mops, mugo pine trees are virtually maintenance-free (barring any insect or disease problems). Their drought tolerance will be especially appreciated in warmer climates. Since their roots grow close to the surface, it is a good idea to mulch around mugo pine trees, to keep the roots cool.
Other Names for Mugo Pine Trees:
You will also see mugo pine trees referred to as "mugho pines," "dwarf mountain pines" and "Swiss mountain pines" (mugo pines are indigenous to Europe).