The Right Place
Creeping junipers tolerate considerable cold and are hardy up to the Canada border (zone 3). They withstand winter temperatures as low as -40° F.
Creeping junipers require full sun, having minimal tolerance for shade. In shade they grow loose and spindly. They like sites with open exposure like prairies, cliffs, old fields, hillsides, and rocky ledges. They like the seashore. They do well in eroded areas, in coarse and sandy soils. They do not mind clay either. They definitely do not like waterlogged soil, which makes them prone to disease. Their versatility is evident also in their willingness to cope with soil that ranges from moderately acid to alkaline (pH 5.0 and 8.5).
Planting Nursery Stock
Creeping junipers are difficult to transplant because they have a deep taproot as well as "creeping" roots that spread like underground stems. If possible, choose shrubs that have been raised in containers rather than ones whose roots are wrapped in a ball with soil in burlap. Spring is the best time to plant.
Remove the juniper from the container or unwrap the rootball if it is burlapped. Gently pull apart and spread any roots that are tangled. Dig a saucer-shaped planting hole wide enough to accommodate the spread roots and as deep as the rootball. Roughen the sloping sides of the hole, but do not place any loose soil in it. Place the shrub in the hole making certain that it is at the same depth that it was in the container. Fill the hole with soil to the level of (or slightly above) the surrounding ground and water thoroughly to provide good soil-to-root contact. Do not fertilize at this time. Keep in mind the shrub's mature spread and space it far enough apart from other shrubs that it won't become overcrowded as it ages.