Different designs as well as manual and powered versions of hedge trimmers exist.
Tractor-mounted and tractor-driven hedge trimmers also exist but are uncommon.
These machines consist of a moveable arm (hydraulic boom) with a large hedge trimmer attachment at its end.
[citation needed] Such large hedge trimmers are often confused with tractor-mounted reach flail mowers (booms with flail mower attachments), which appear similar due to the use of booms.
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 maintenance, etc.).