Juniperus horizontalis
Creeping Juniper
Cupressaceae
ExpandHabitat
- zone 4
- native to northern North America
- often found on gravely slopes and rocky seaside locations
Habit and Form
- dense, evergreen shrub
- branches very long and flexible
- branches form large mats
- 1' to 2' tall and 4' to 8' wide
- medium growth rate
- medium texture
Summer Foliage
- glaucous needles
- two kinds of needles: awl-shaped and scale-like
- scales are closely pressed to stem and found in a four rank pattern
- awls are found in opposite pairs
- needle tip sharply pointed
- green to blue-green
Autumn Foliage
- evergreen, no fall color
- needles turn somewhat purple in cold months
Flowers
- dioecious
- no ornamental value
Fruit
- 2 to 3-seeded berry-like cone
- found on recurved stalks
- 0.25" to 0.33" in diameter
- blue in color
Bark
- reddish brown and peeling
- hard to see because of overlapping branches
Culture
- easily transplanted
- adaptable to most conditions
- full sun
- pH adaptable
- salt tolerant
Landscape Use
- groundcover
- erosion control
- planters
- mass plantings
Liabilities
- Juniper blight and spider mites do cause some problems
ID Features
- two types of leaves present
- purple winter color
- needles pointed
- loose and floppy branches
- blue-green summer color
- spreading growth habit
Propagation
- by cuttings
Cultivars/Varieties
'Bar Harbor' - A good, prostrate groundcover, this plant has blue-gray foliage in summer that shades blue-purple in the winter. It grows about 1' tall and spreads to 6' wide. It is a male clone, but several clones may be in the trade under the name 'Bar Harbor'. This cultivar originated from Mt. Desert Island, Maine. It is a proven groundcover that is tolerant of salt spray and fast growing.
'Blue Chip' - This prostrate grower maintains its steel-blue foliage all year and grows 8' to 10' wide, but only 8" to 10" tall. It may be more sensitive to Phomopsis blight than other types.
'Blue Prince' - This selection out of Alberta, Canada possesses very fine blue needle color. It is a low, ground-hugging form growing 6" tall and up to 5' wide.
'Hughes' - The silver-blue foliage of this selection turns slightly purple in the winter. It grows 9' wide and 1' tall with distinct radial branching.
'Monber' (Icee Blue) - This 'Wiltonii' sport has silver-blue foliage and grows 4" tall and 8' wide. The mature branches are tipped purple.
'Mother Lode' - This sport of 'Wiltonii' has distinctive gold variegated foliage. The yellow portion of the leaves turns orangish come winter. It grows slowly and hugs the ground, spreading 4" to 6" per year and reaching only 3" tall with a spread of 3'.
'Plumosa' - Known as the "Andorra Juniper", this is one of the most common landscape junipers despite its susceptibility to blight. It is a dense, compact grower reaching 2' tall and up to 10' wide. The summer foliage is bluish-green, becoming more purplish in winter.
'Plumosa Compacta' and 'Plumosa Compacta Youngstown' - These forms appear to be identical, appearing as dwarf forms of 'Plumosa' with a dense, flat growth habit to 18" tall and many feet wide. The foliage is gray-green and deepens to purple in winter.
'Prince of Wales' - This cold hardy selection out of Canada forms a low mat 6" high with bright green foliage that tinges slightly purple in winter.
'Wiltoni' (also known as 'Wiltonii' and 'Blue Rug') - This is perhaps the standard against which all other low, prostrate junipers are to be judged. It forms a dense mat of blue foliage 4"-6" high and up to 5' wide. The foliage turns slightly purple in winter exposure. This plant has proven very useful when used as a groundcover or bank planting. It was originally found on Vinalhaven Island in Penobscot Bay, Maine and introduced by South Wilton Nurseries, Wilton, CT. It is very salt and wind tolerant.