| Juniperus horizontalis | |
|---|---|
 | |
| Foliage and cones | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Gymnospermae |
| Division: | Pinophyta |
| Class: | Pinopsida |
| Order: | Cupressales |
| Family: | Cupressaceae |
| Genus: | Juniperus |
| Species: | J. horizontalis |
| Binomial name | |
| Juniperus horizontalis Moench 1794 | |
 | |
| Natural range ofJuniperus horizontalis | |
| Synonyms[3] | |
Juniperus horizontalis, thecreeping juniper orcreeping cedar,[4] is a low-growingshrubbyjuniper native to northernNorth America, throughout most ofCanada fromYukon east toNewfoundland, and in some of the northernUnited States.
Living up to both its scientific and common names, the species reaches only 10–30 centimetres (3+7⁄8–11+3⁄4 in) tall but often spreading several metres wide. The shoots are slender,0.7–1.2 millimetres (1⁄32–1⁄16 in) diameter. Theleaves are arranged in opposite decussate pairs, or occasionally in whorls of three; the adult leaf blades are scale-like, 1–2 mm long (to 8 mm on lead shoots) and1–1.5 mm (1⁄32–1⁄16 in) broad, and derive from an adnatepetiole. The juvenile leaves (on young seedlings only) are needle-like,5–10 mm (3⁄16–3⁄8 in) long. Thecones are berry-like, globose to bilobed,5–7 mm (3⁄16–9⁄32 in) in diameter, dark blue with a pale blue-white waxy bloom, and contain twoseeds (rarely one or three); they usually have a curved stem and are mature in about 18 months. The male cones are2–4 mm (3⁄32–5⁄32 in) long, and shed their pollen in early spring. It isdioecious, producing cones of only one sex on each plant.
It is closely related toJuniperus virginiana, and oftenhybridizes with it where their ranges meet in southernCanada. Hybrids withJuniperus scopulorum also occur.
The species is native to northernNorth America, throughout most of Canada fromYukon east toNewfoundland, and in theUnited States inAlaska, and continentally fromMontana east toMaine, reaching its furthest south inWyoming and northernIllinois. Amongst the sites it occupies are rocky areas of the east slopes of theRocky Mountains.[5]
Well over 100 differentcultivars have been selected for use asornamental plants in gardens, their strictly prostrate growth habit being valued for ground cover. Popular examples include 'Bar Harbor', 'Blue Acres', 'Emerald Spreader', 'Green Acres', and 'Wiltonii' ("Blue Rug Juniper"). Many of the most popular cultivars have strikingly glaucous foliage, while others are bright green, yellowish or variegated.
