A prostrate shrub is a woody plant

Woody plant

A woody plant is a plant that uses wood as its structural tissue. These are typically perennial plants whose stems and larger roots are reinforced with wood produced adjacent to the vascular tissues. The main stem, larger branches, and roots of these plants are usually covered by a layer of...

, most of the branches of which lie upon or just under the ground, rather than being held erect as are the branches of most trees and shrubs.

Prostration may occur because the supporting tissues in stems are not strong enough to support the weight of the plant, causing the plant to bend until it reaches the ground. Alternatively, it may occur because of a genetic disposition for branches to grow horizontally on or just under the ground; for example, as a strategy to avoid overly strong sunlight. Finally, environmental factors such as strong winds laden with sand or salt may tend to prune away erect branches, thereby creating a prostrate habit in plants that may not be predisposed to prostration.

Prostrate shrubs are used in horticulture

Horticulture

Horticulture is the industry and science of plant cultivation including the process of preparing soil for the planting of seeds, tubers, or cuttings. Horticulturists work and conduct research in the disciplines of plant propagation and cultivation, crop production, plant breeding and genetic...

 as groundcover

Groundcover

Groundcover refers to any plant that grows over an area of ground, used to provide protection from erosion and drought, and to improve its aesthetic appearance .- Ecosystem :...

s and in hanging basket

Hanging basket

A hanging basket is a suspended container used for growing decorative plants. Typically they are hung from buildings, where garden space is at a premium, and from street furniture for environmental enhancement. They may also be suspended from free standing frames sometimes called hanging basket trees...

s, and to bind soils and prevent erosion in remedial landscaping

Landscape architecture

Landscape architecture is the design of outdoor and public spaces to achieve environmental, socio-behavioral, or aesthetic outcomes. It involves the systematic investigation of existing social, ecological, and geological conditions and processes in the landscape, and the design of interventions...

. They are also important components of rock gardens. The shrinking size of urban gardens

Urban horticulture

Urban and peri-urban horticulture includes all horticultural crops grown for human consumption and ornamental use within and in the immediate surroundings of cities. Although crops have always been grown inside the city, the practice is expanding and gaining more attention...

 has meant an increase in demand for and desirability of dwarf and prostrate forms of many garden plants. More recently, prostrate shrubs have received attention for their usefulness in planting green roof

Green roof

A green roof is a roof of a building that is partially or completely covered with vegetation and a growing medium, planted over a waterproofing membrane. It may also include additional layers such as a root barrier and drainage and irrigation systems...

s and green walls, where they can contribute to environmental conservation

Environmental engineering

Environmental engineering is the application of science and engineering principles to improve the natural environment , to provide healthy water, air, and land for human habitation and for other organisms, and to remediate polluted sites...

.

Prostrate plant forms may arise from deliberate breeding and hybridisation, such as the groundcover grevillea

Grevillea

Grevillea is a diverse genus of about 360 species of evergreen flowering plants in the protea family Proteaceae, native to Australia, New Guinea, New Caledonia, and Sulawesi. It was named in honour of Charles Francis Greville. The species range from prostrate shrubs less than 0.5 m tall to trees...

s, including Grevillea "Poorinda Royal Mantle", and G. "Bronze Rambler", or by selection of forms of plants growing in exposed areas. The windswept coastal heathlands and cliffs of far southeastern New South Wales have yielded Banksia 'Roller Coaster'

Banksia 'Roller Coaster'

Banksia 'Roller Coaster, sometimes referred to as Banksia 'Austraflora Roller Coaster, is a registered Banksia cultivar bred from Banksia integrifolia subsp. integrifolia. Its extended cultivar name is Banksia integrifolia 'Roller Coaster...

 and Banksia 'Pygmy Possum'

Banksia 'Pygmy Possum'

Banksia 'Pygmy Possum, formerly Banksia 'Austraflora Pygmy Possum, and also known by its extended cultivar name Banksia serrata 'Pygmy Possum, is a registered Banksia cultivar...

. These are flattened varieties of less than 0.5 m in height of the species Banksia integrifolia

Banksia integrifolia

Banksia integrifolia, commonly known as Coast Banksia, is a species of tree that grows along the east coast of Australia. One of the most widely distributed Banksia species, it occurs between Victoria and Central Queensland in a broad range of habitats, from coastal dunes to mountains...

and Banksia serrata

Banksia serrata

Banksia serrata, commonly known as Old Man Banksia, Saw Banksia, Saw-tooth Banksia and Red Honeysuckle, is a species of woody shrub or tree of the genus Banksia in the Proteaceae family. Native the east coast of Australia, it is found from Queensland through to Victoria with outlying populations on...

, respectively, both of which grow to sizeable trees of 10 m (30 ft) or more in height. The origin of others is unclear; Cootamundra Wattle (Acacia baileyana) is a popular and widely used garden plant in Australia, a prostrate form of which is also in cultivation. Its origin is unknown, possibly a chance seedling in cultivation. It itself is a popular garden plant, its cascading horizontal branches good for rockeries. Many species of roses grow as long canes that can spread prostrate on the ground, and some of these have been hybridized to form climbing and rambling roses that can be allowed to grow on the ground without support, as well as varieties known as "carpet roses" that are intended to be grown as ground covers. Prostrate juniper, Juniperus communis subsp. alpina

Juniperus communis

Juniperus communis, the Common Juniper, is a species in the genus Juniperus, in the family Cupressaceae. It has the largest range of any woody plant, throughout the cool temperate Northern Hemisphere from the Arctic south in mountains to around 30°N latitude in North America, Europe and Asia.-...

 is a naturally occurring form of a popular evergreen

Evergreen

In botany, an evergreen plant is a plant that has leaves in all seasons. This contrasts with deciduous plants, which completely lose their foliage during the winter or dry season.There are many different kinds of evergreen plants, both trees and shrubs...

. Many species of Cotoneaster

Cotoneaster

Cotoneaster is a genus of woody plants in the rose family, Rosaceae, native to the Palaearctic region , with a strong concentration of diversity in the genus in the mountains of southwestern China and the Himalayas...

, such as C. apiculatus, are prostrate ornamentals, as are the closely related Pyracantha

Pyracantha

Pyracantha is a genus of thorny evergreen large shrubs in the family Rosaceae, with common names Firethorn or Pyracantha. They are native to an area extending from Southeast Europe east to Southeast Asia, resemble and are related to Cotoneaster, but have serrated leaf margins and numerous thorns...

s, and the humilis variant of sweetbox, Sarcococca

Sarcococca

Sarcococca, Sweet box, or Christmas box is a genus of 16-20 species of flowering plants in the family Buxaceae, native to eastern and southeastern Asia and the Himalaya. They are slow-growing evergreen shrubs 1-2 m tall. The leaves are borne alternately, 3-12 cm long and 1-4 cm broad. They bear...

 hookeriana var. humilis. Heaths (Erica carnea

Erica carnea

Erica carnea is a species of heath native to mountainous areas of central and southern Europe in the eastern Alps, where it grows in coniferous woodlands or stony slopes.It is a low-growing subshrub reaching 10-25 cm tall, with evergreen needle-like leaves...

and related species) and heathers (Calluna vulgaris

Calluna

Calluna vulgaris is the sole species in the genus Calluna in the family Ericaceae. It is a low-growing perennial shrub growing to tall, or rarely to and taller, and is found widely in Europe and Asia Minor on acidic soils in open sunny situations and in moderate shade...

) are prostrate shrubs often featured prominently in rock gardens. Wintergreens such as Gaultheria humifusa

Gaultheria humifusa

Gaultheria humifusa is a species of shrub in the heath family which is known by the common names alpine wintergreen and alpine spicy wintergreen. It is native to western North America, from British Columbia to California to Colorado, where it grows in moist subalpine mountain forests...

and Gaultheria procumbens are also prostrate growers. Although, strictly speaking, herbaceous, the North American bunchberry (Cornus canadensis

Cornus canadensis

Cornus canadensis is a herbaceous member of the Cornaceae family...

), a member of the dogwood

Dogwood

The genus Cornus is a group of about 30-60 species of woody plants in the family Cornaceae, commonly known as dogwoods. Most dogwoods are deciduous trees or shrubs, but a few species are nearly herbaceous perennial subshrubs, and a few of the woody species are evergreen...

 genus, can appear as a prostrate shrub when growing in the garden. Many daphnes

Daphne (plant)

Daphne is a genus of between 50 and 95 species of deciduous and evergreen shrubs in the family Thymelaeaceae, native to Asia, Europe, and north Africa...

, particularly those derived from Daphne odora

Daphne odora

Daphne odora is an evergreen shrub, grown for its very fragrant, fleshy, pale-pink, tubular flowers, each with 4 spreading lobes, and for its glossy foliage. It rarely fruits, but when it does, it produces red berries after flowering....

, are prostrate growers, including forms that are highly fragrant and have variegated leaves, although they are short-lived. Some forms of the culinary herb

Herb

Except in botanical usage, an herb is "any plant with leaves, seeds, or flowers used for flavoring, food, medicine, or perfume" or "a part of such a plant as used in cooking"...

 rosemary

Rosemary

Rosemary, , is a woody, perennial herb with fragrant, evergreen, needle-like leaves and white, pink, purple or blue flowers, native to the Mediterranean region. It is a member of the mint family Lamiaceae, which includes many other herbs, and is one of two species in the genus Rosmarinus...

 (Rosmarinus officinalis) form prostrate shrubs when grown in Mediterranean climate

Mediterranean climate

A Mediterranean climate is the climate typical of most of the lands in the Mediterranean Basin, and is a particular variety of subtropical climate...

s, although they die back to the ground when grown where winters are colder.