A hedge trimmer, shrub trimmer, or bush trimmer, is a gardening tool

Garden tool

A garden tool is any one of many tools made for gardens and gardening and overlaps with the range of tools made for agriculture and horticulture...

 or machine used for trimming (cutting, pruning

Pruning

Pruning is a horticultural practice involving the selective removal of parts of a plant, such as branches, buds, or roots. Reasons to prune plants include deadwood removal, shaping , improving or maintaining health, reducing risk from falling branches, preparing nursery specimens for...

) hedge

Hedge

Hedge may refer to:* Hedge or hedgerow, line of closely spaced shrubs planted to act as a barrier* Hedge , investment made to limit loss* Hedge , intentionally non-committal or ambiguous sentence fragments-See also:...

s or solitary shrub

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...

s (bushes). Different designs as well as manual and powered versions of hedge trimmers exist.

Stand-alone hedge trimmers

The power source of stand-alone hedge trimmers can be human power

Human power

Human power is work or energy that is produced from the human body. It can also refer to the power of a human. Power comes primarily from muscles, but body heat is also used to do work like warming shelters, food, or other humans....

, gasoline

Gasoline

Gasoline , or petrol , is a toxic, translucent, petroleum-derived liquid that is primarily used as a fuel in internal combustion engines. It consists mostly of organic compounds obtained by the fractional distillation of petroleum, enhanced with a variety of additives. Some gasolines also contain...

, or electricity

Electricity

Electricity is a general term encompassing a variety of phenomena resulting from the presence and flow of electric charge. These include many easily recognizable phenomena, such as lightning, static electricity, and the flow of electrical current in an electrical wire...

.

• Manual hedge trimmers (sometimes also called hedge shears, or hedge clippers) are designed as large scissors
  Scissors
  Scissors are hand-operated cutting instruments. They consist of a pair of metal blades pivoted so that the sharpened edges slide against each other when the handles opposite to the pivot are closed. Scissors are used for cutting various thin materials, such as paper, cardboard, metal foil, thin...
  
   or large pruning shears
  Pruning shears
  Pruning shears, also called hand pruners , or secateurs are a type of scissors for use with plants. They are strong enough to prune hard branches of trees and shrubs, sometimes up to two centimetres thick...
  
  . They do not need anything to operate and are cheapest/most environmentally friendly.
• Motorized hedge trimmers allow work to be done faster and with less effort than manual ones. Their cutting mechanism is similar to that of finger-bar mowers
  Mower
  A mower is a machine for cutting grass or other plants that grow on the ground. Usually mowing is distinguished from reaping, which uses similar implements, but is the traditional term for harvesting grain crops, e.g...
  
  . Powered trimmers are generally designed with safety devices such that they work only when both of the operator's hands are on the handles.
  • Gasoline-powered trimmers tend to be more powerful but can be heavier and more difficult to start.
  • Electrical trimmers tend to be lighter and less powerful (than gasoline variants) as well as less polluting/noisy, yet still require an electrical cord with most types (if not equipped with rechargeable batteries
    Rechargeable battery
    A rechargeable battery or storage battery is a group of one or more electrochemical cells. They are known as secondary cells because their electrochemical reactions are electrically reversible. Rechargeable batteries come in many different shapes and sizes, ranging anything from a button cell to...
    
    ).

Tractor-mounted hedge trimmers

Tractor

Tractor

A tractor is a vehicle specifically designed to deliver a high tractive effort at slow speeds, for the purposes of hauling a trailer or machinery used in agriculture or construction...

-mounted and tractor-driven hedge trimmers also exist, but are not that common. These machines

Agricultural machinery

Agricultural machinery is machinery used in the operation of an agricultural area or farm.-Hand tools:The first person to turn from the hunting and gathering lifestyle to farming probably did so by using his bare hands, and perhaps some sticks or stones. Tools such as knives, scythes, and wooden...

 consist of a moveable arm (hydraulic

Hydraulic machinery

Hydraulic machines are machinery and tools that use liquid fluid power to do simple work. Heavy equipment is a common example.In this type of machine, hydraulic fluid is transmitted throughout the machine to various hydraulic motors and hydraulic cylinders and which becomes pressurised according to...

 boom) with a large hedge trimmer attachment at its end. Their cutting mechanism is similar to that of finger-bar mowers

Mower

A mower is a machine for cutting grass or other plants that grow on the ground. Usually mowing is distinguished from reaping, which uses similar implements, but is the traditional term for harvesting grain crops, e.g...

.

Such large hedge trimmers are often confused with tractor-mounted reach flail mowers

Flail mower

A flail mower is a type of PTO driven implement that can attach to the three-point hitches found on the rear of most tractors. This type of mower is best used to provide a rough cut to taller grass where contact with loose debris may be possible such as roadsides.The flail mower gets its name from...

 (booms with flail mower attachments), which appear similar due to the use of booms. And in colloquial language

Colloquial language

Colloquial language, especially in philosophy of language, is natural language which, among other properties, uses colloquialisms. In the field of logical atomism, meaning is evaluated differently than with more formal propositions.-See also:...

 both, tractor-mounted hedge trimmers and reach flail mowers, are called – rather imprecisely – hedge cutters, or brush cutters. In contrast to tractor-mounted hedge trimmers, reach flail mowers have a different cutting mechanism, and are not only used for trimming hedges, but also in several other fields of application (mowing taller grass, road verge cutting, ditch

Ditch

A ditch is usually defined as a small to moderate depression created to channel water.In Anglo-Saxon, the word dïc already existed and was pronounced 'deek' in northern England and 'deetch' in the south. The origins of the word lie in digging a trench and forming the upcast soil into a bank...

 maintenance, etc.).
Furthermore some special machines allow easy trimming of specific plants or food crops, and are sometimes just called trimmers, too. These include e.g. vine trimmers (for grapevine

Vitis

Vitis is a genus of about 60 species of vining plants in the flowering plant family Vitaceae. The genus is made up of species predominantly from the Northern hemisphere. It is economically important as the source of grapes, both for direct consumption of the fruit and for fermentation to produce...

), and tree trimmers ("tree toppers"). Their cutting mechanisms can be very different from hedge trimmers.