Pronounciation: Ju-NIP-er-us hor-i-zon-TAL-is
Sunset 4-24 (zone 12 with some protection from the high heat and strong western light)
USDA 3 (some protection might be needed)-11
Landscape Use: Small to medium scale ground cover for a natural informally looking carpet, rock gardens, raised planters where it is allowed to drape over the edge to cover a planter bed wall.
Form & Character: Demure, spreading, prostrate, coniferous, and oriental (or maybe Canadian?).
Growth Habit: Woody evergreen perennial, low, prostrate and spreading to a radius of 6 to 15 feet with a height of 4 to 24 inches depending on cultivar.
Foliage/texture: Creeping juniper can hav a mixture of adult (appressed, scale like) and juvenile (stiff short needle-like, ternate) foliage, opposite. Most cultivar selections are mostly foliated with very short adult (appressed) leaves. Foliar colors varies from dark green to glaucous blue depending on cultivar; fine texture.
Flowers & fruits: All junipers are dioecious; female cones sub-globose to 5/16 inch across, 2-3 seeded, ripen in 2-3 years, purplish to brown; male flowers axillary and very small, golden yellow to brown, spring, inconspicuous
Seasonal color: Absolutely none in Phoenix, though in colder climates the foliage turns bronze or purple during the coldest times of winter.
Temperature: Tolerant to 115oF. But consider this....if the Phoenix ambient air temperature is 110oF (a typical balmy June afternoon), then how hot do you think it is at the ground surface where creeping juniper is trying to survive? Yeah, that's right...around 135 to 145oF. Ouch!!!
Light: Full sun to partial shade, no western exposures in Phoenix.
Soil: Very tolerant, but somewhat salt sensitive.
Watering: Deep summer irrigations are required in Phoenix for survival.
Pruning: No regular pruning needed. If in time, creeping juniper becomes overgrown, the practice selective branch removal and subtle heading cuts on other branches.
Propagation: Creeping juniper cultivars are propagated from cuttings which generally root readily.
Disease and pests: Spider mites and juniper scale.
Additional comments: Creeping juniper is quite difficult to grow in Phoenix unless there is some partial shade, but it thrives in other higher elevation Arizona towns and cities. There are well over 100 named cultivars. Longstanding popular examples include 'Bar Harbor', 'Blue Acres', 'Emerald Spreader', 'Green Acres', and 'Wiltonii'.