Juniperus horizontalis (
Creeping Juniper) is a low-growing
shrubA shrub or bush is a horticultural rather than strictly botanical category of woody plant, distinguished from a tree by its multiple stems and lower height, usually less than 5-6 m tall. A large number of plants can be either shrubs or trees, depending on the growing conditions they experience...
by
juniperJunipers 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 AmericaNorth America is the northern continent of the Americas, situated in the Earth's northern hemisphere and in the western hemisphere. It is bordered on the north by the Arctic Ocean, on the east by the North Atlantic Ocean, on the southeast by the Caribbean Sea, and on the west by the North Pacific...
, throughout most of
CanadaCanada is a country occupying most of northern North America, extending from the Atlantic Ocean in the east to the Pacific Ocean in the west and northward into the Arctic Ocean...
from
YukonYukon , or The Yukon, is the westernmost and smallest of Canada's three federal territories. It was named after the Yukon River, Yukon meaning "Great River" in Gwich’in....
east to Newfoundland, and in the
United StatesThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
in
AlaskaAlaska is the largest state of the United States of America 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
MontanaMontana is a state in the Western United States. The western third of the state contains numerous mountain ranges; other '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
MaineThe State of Maine is a state in the New England region of the northeastern United States, bordering the Atlantic Ocean to the southeast, New Hampshire to the southwest, and the Canadian provinces of Quebec to the northwest and New Brunswick to the northeast. Maine is the northernmost portion of...
, reaching its furthest south in
WyomingWyoming is a state in the Western United States. The majority of the state is dominated by the mountain ranges and rangelands of the Rocky Mountain West, while the easternmost section of the state includes part of a high elevation prairie region known as the High Plains. While the tenth largest...
and northern
IllinoisIllinois , the 21st state admitted to the United States of America, is the most populous and demographically diverse Midwestern state and the fifth most populous state in the nation...
.
It lives up to both its scientific and common names, reaching only 10-30 cm tall but often spreading several
metreThe metre or meter is the basic unit of length in the International System of Units . Historically, the metre was defined by the French Academy of Sciences as the length between two marks on a platinum-iridium bar, which was designed to represent one ten-millionth of the distance from the Equator...
s wide.
Juniperus horizontalis (
Creeping Juniper) is a low-growing
shrubA shrub or bush is a horticultural rather than strictly botanical category of woody plant, distinguished from a tree by its multiple stems and lower height, usually less than 5-6 m tall. A large number of plants can be either shrubs or trees, depending on the growing conditions they experience...
by
juniperJunipers 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 AmericaNorth America is the northern continent of the Americas, situated in the Earth's northern hemisphere and in the western hemisphere. It is bordered on the north by the Arctic Ocean, on the east by the North Atlantic Ocean, on the southeast by the Caribbean Sea, and on the west by the North Pacific...
, throughout most of
CanadaCanada is a country occupying most of northern North America, extending from the Atlantic Ocean in the east to the Pacific Ocean in the west and northward into the Arctic Ocean...
from
YukonYukon , or The Yukon, is the westernmost and smallest of Canada's three federal territories. It was named after the Yukon River, Yukon meaning "Great River" in Gwich’in....
east to Newfoundland, and in the
United StatesThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
in
AlaskaAlaska is the largest state of the United States of America 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
MontanaMontana is a state in the Western United States. The western third of the state contains numerous mountain ranges; other '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
MaineThe State of Maine is a state in the New England region of the northeastern United States, bordering the Atlantic Ocean to the southeast, New Hampshire to the southwest, and the Canadian provinces of Quebec to the northwest and New Brunswick to the northeast. Maine is the northernmost portion of...
, reaching its furthest south in
WyomingWyoming is a state in the Western United States. The majority of the state is dominated by the mountain ranges and rangelands of the Rocky Mountain West, while the easternmost section of the state includes part of a high elevation prairie region known as the High Plains. While the tenth largest...
and northern
IllinoisIllinois , the 21st state admitted to the United States of America, is the most populous and demographically diverse Midwestern state and the fifth most populous state in the nation...
.
It lives up to both its scientific and common names, reaching only 10-30 cm tall but often spreading several
metreThe metre or meter is the basic unit of length in the International System of Units . Historically, the metre was defined by the French Academy of Sciences as the length between two marks on a platinum-iridium bar, which was designed to represent one ten-millionth of the distance from the Equator...
s wide. The shoots are slender, 0.7-1.2 mm diameter. The
leavesIn botany, a leaf is an above-ground plant organ specialized for photosynthesis. For this purpose, a leaf is typically flat and thin. There is continued debate about whether the flatness of leaves evolved to expose the chloroplasts to more light or to increase the absorption of carbon dioxide. In...
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
conesA 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
seedA seed , referred to as a kernel in some plants, 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
dioeciousPlant 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 virginianaJuniperus 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 scopulorumJuniperus 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
cultivarA cultivar is a cultivated plant that has been selected and given a unique name because of desired characteristics; it is usually distinct from similar plants and when propagated it retains those characteristics....
s have been selected for use as
ornamental plantOrnamental plants are typically grown in the flower garden or as house plants. Most commonly they are grown for the display of their flowers. Other common ornamental features include leaves, scent, fruit, stem and bark. In some cases, unusual features may be considered ornamental, such as the...
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.