Juniperus horizontalis
Encyclopedia
Juniperus horizontalis (Creeping Juniper or Creeping cedar) is a low-growing shrub
by juniper
native to northern North America
, throughout most of Canada
from Yukon
east to Newfoundland, and in the United States
in Alaska
, and locally from Montana
east to Maine
, reaching its furthest south in Wyoming
and northern Illinois
.
It lives up to both its scientific and common names, reaching only 10-30 cm tall but often spreading several metres wide. The shoots are slender, 0.7-1.2 mm diameter. The leaves
are arranged in opposite decussate pairs, or occasionally in whorls of three; the adult leaves are scale-like, 1-2 mm long (to 8 mm on lead shoots) and 1-1.5 mm broad. The juvenile leaves (on young seedlings only) are needle-like, 5-10 mm long. The cones
are berry-like, globose to bilobed, 5-7 mm in diameter, dark blue with a pale blue-white waxy bloom, and contain two seed
s (rarely one or three); they usually have a curved stem and are mature in about 18 months. The male cones are 2-4 mm long, and shed their pollen in early spring. It is dioecious
, producing cones of only one sex on each plant.
It is closely related to Juniperus virginiana
, and often hybridizes with it where their ranges meet in southern Canada. Hybrids with Juniperus scopulorum
also occur.
s have been selected for use as ornamental plant
s 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.
Shrub
A shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...
by juniper
Juniper
Junipers are coniferous plants in the genus Juniperus of the cypress family Cupressaceae. Depending on taxonomic viewpoint, there are between 50-67 species of juniper, widely distributed throughout the northern hemisphere, from the Arctic, south to tropical Africa in the Old World, and to the...
native to northern North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
, throughout most of Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
from Yukon
Yukon
Yukon is the westernmost and smallest of Canada's three federal territories. It was named after the Yukon River. The word Yukon means "Great River" in Gwich’in....
east to Newfoundland, and in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
in Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...
, and locally from Montana
Montana
Montana is a state in the Western United States. The western third of Montana contains numerous mountain ranges. Smaller, "island ranges" are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name,...
east to Maine
Maine
Maine is a state in the New England region of the northeastern United States, bordered by the Atlantic Ocean to the east and south, New Hampshire to the west, and the Canadian provinces of Quebec to the northwest and New Brunswick to the northeast. Maine is both the northernmost and easternmost...
, reaching its furthest south in Wyoming
Wyoming
Wyoming is a state in the mountain region of the Western United States. The western two thirds of the state is covered mostly with the mountain ranges and rangelands in the foothills of the Eastern Rocky Mountains, while the eastern third of the state is high elevation prairie known as the High...
and northern Illinois
Illinois
Illinois is the fifth-most populous state of the United States of America, and is often noted for being a microcosm of the entire country. With Chicago in the northeast, small industrial cities and great agricultural productivity in central and northern Illinois, and natural resources like coal,...
.
Leaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....
are arranged in opposite decussate pairs, or occasionally in whorls of three; the adult leaves are scale-like, 1-2 mm long (to 8 mm on lead shoots) and 1-1.5 mm broad. The juvenile leaves (on young seedlings only) are needle-like, 5-10 mm long. The cones
Conifer cone
A cone is an organ on plants in the division Pinophyta that contains the reproductive structures. The familiar woody cone is the female cone, which produces seeds. The male cones, which produce pollen, are usually herbaceous and much less conspicuous even at full maturity...
are berry-like, globose to bilobed, 5-7 mm in diameter, dark blue with a pale blue-white waxy bloom, and contain two seed
Seed
A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...
s (rarely one or three); they usually have a curved stem and are mature in about 18 months. The male cones are 2-4 mm long, and shed their pollen in early spring. It is dioecious
Plant sexuality
Plant sexuality covers the wide variety of sexual reproduction systems found across the plant kingdom. This article describes morphological aspects of sexual reproduction of plants....
, producing cones of only one sex on each plant.
It is closely related to Juniperus virginiana
Juniperus virginiana
Juniperus virginiana is a species of juniper native to eastern North America, from southeastern Canada to the Gulf of Mexico, east of the Great Plains...
, and often hybridizes with it where their ranges meet in southern Canada. Hybrids with Juniperus scopulorum
Juniperus scopulorum
Juniperus scopulorum is a species of juniper native to western North America, in Canada in British Columbia and southwest Alberta, in the United States from Washington east to North Dakota, south to Arizona and also locally western Texas, and northernmost Mexico from Sonora east to Coahuila...
also occur.
Cultivation and uses
Well over 100 different cultivarCultivar
A cultivar'Cultivar has two meanings as explained under Formal definition. When used in reference to a taxon, the word does not apply to an individual plant but to all those plants sharing the unique characteristics that define the cultivar. is a plant or group of plants selected for desirable...
s have been selected for use as ornamental plant
Ornamental plant
Ornamental plants are plants that are grown for decorative purposes in gardens and landscape design projects, as house plants, for cut flowers and specimen display...
s 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.