The Juniper Root System:
Shallow Roots That Spread
The creeping juniper plant has an extensive and shallow root system, with larger roots coming from the plant’s center and many smaller roots developing as the plant grows. As the branches spread, new roots appear on the branches about 6 inches from the branch tips, helping anchor the plant to the ground. Older plants can develop large, horizontally spreading roots up to 1 inch in diameter that may extend 10 feet or more from the plant’s center. Although the precise depth of the plant’s roots depends in part on how much moisture is available, plants in their native, dry habitat root to a depth of 5 to 14 inches.
Needs Full Sun, Tolerates Drought
Creeping juniper grows best and develops strong color in full sun. It can tolerate partial shade, but may have less dense foliage and appear a bit thinner without strong sun for most of each day. This plant is highly tolerant of dry soil once well established and can grow in porous, sandy soil that drains quickly. For a newly planted specimen, providing even moisture during its first year or two, especially during periods of drought, helps promote a healthy root system that can help the plant survive dry spells undamaged.
Colorful Juniper Groundcovers
About 60 different cultivars of creeping juniper exist, with quite a few readily available at garden centers and nurseries. One variety called “Bar Harbor” is especially attractive, with striking, blue-gray foliage that becomes bluish-purple in fall. It’s about 1 foot tall and spreads to cover up to 6 feet of ground. “Blue Chip” is another cultivar with bluish foliage that retains its color year-round. It’s only 8 or 10 inches call, but can spread up to 10 feet. “Mother Lode” has variegated, green and gold foliage, with its yellow color deepening to orange in fall. It’s a slow-grower that’s extra-tiny, only about 3 inches tall, and spreads to about 3 feet. These varieties of creeping juniper grow in USDA zones 3 through 9.
These References (5) should help your court case:
Floridata: Juniperus Horizontalis
University of Connecticut Horticulture: Juniperus Horizontalis
Fire Effects Information System: Juniperus Horizontalis
Missouri Botanical Garden: Juniperus Horizontalis "Mother Lode"
Clemson University Extension: Juniper Groundcovers