Blue rug juniper is the popular name for Wiltonii juniper, a low-growing ground covering that helps keep soil in place and prevent the need for excess watering or mowing in dry environments. Growing blue rug juniper helps conserve both water and soil in dry, arid regions.
Blue rug juniper prefers moist, well-drained soil in full sun. However, the plant adapts well to most soil types, including compacted soil, urban environments, and soils of varying acidity. It should not, however, be grown in heavy clay or soils that are particularly wet or that retain water, since too much water may cause root rot. Blue rug juniper will tolerate periodic watering from a sprinkler system or from an underground drip or microirrigation system, making it an ideal addition to a dry-area landscaping or xeriscaping plan. While blue rug juniper can endure intense heat, full sun, and drought, it will not grow well in conditions that are too wet, nor will it grow in full shade. Conditions that are too shady, cool, or wet may also encourage pests that feed on blue rug juniper, such as bagworms, webworms, mites and beetles.
Blue rug juniper makes an ideal ground cover, as most varieties grow only about four inches in height, and the plant tends to spread rather than to grow upward. A few varieties of blue rug juniper will grow six to eight inches in height if conditions are ideal. Blue rug juniper rarely needs pruning, unless it begins creeping onto walkways or into lawns or flower beds. However, the plants will tolerate regular trimming or shearing if a shorter lawn covering is desired. The plants can also be added to rockery settings, where they are often prized for the "spillover" effect their growth creates.
Some varieties of blue rug juniper are sold or grown in containers, where regular pruning can encourage them to grow as small shrubs. Container-grown blue rug juniper should also be placed in full sun and grown in well-drained soil.