When you spend time and money planning your landscape, you don’t want to find out later that some plants have suffered because you put them in the ground at the wrong time of year. While fairly hardy, creeping juniper (Juniperus horizontalis) does best if you plant it in the right season -- so get it in the ground while the soil is warm.
Hardy in U.S. Department of Agriculture plant hardiness zones 3 through 9, creeping juniper is native to the northern part of North America, growing in Alaska down through Canada into the upper United States, from Montana to New York. Although it only grows to a height of 6 to 18 inches, its spread can be as wide as 10 feet, and is usually at least 4. Dense, evergreen foliage is composed of both scales and needles, and is usually green or blue-green during the growing season. During the winter months, when the plant is in dormancy, creeping juniper may take on a purple hue.
Plant creeping juniper in spring, summer or early fall. Once the weather changes in mid-fall, it's too late. The main consideration with creeping juniper -- and most evergreens -- is that they often do not weather colder winter months well if they have not had time to acclimate to their new location. Root establishment is important for proper hydration through the winter. If creeping juniper doesn’t have a chance to become established, its roots may not be able to replace water loss through the leaves, and the plant can dry out, leading to burning and scorching.
Before you dig a hole in the garden, make sure there's no danger of rupturing any water, sewer or gas lines. If you aren’t sure where they are, you can call your utility companies and make an appointment -- usually free -- for them to mark the area for you. Also keep in mind that creeping juniper has medium water needs. Do not try to grow it close to plants with drastically different needs, such as in a rain garden or a low-water desert garden.
Creeping juniper will grow in a range of soil types and adapts to most pH levels. It is a tolerant plant in general, and takes kindly to transplanting during the right time of year. Plant it where it will receive full sun, and provide it with consistent moisture. The plant also controls erosion -- if you have a bank or bed that suffers from dirt runoff during dry summer months or rainy winter ones, creeping juniper might be the plant for you.