Shrubs, plants such as ligustrum, euonymus, myrtle and rosemary are used as hedges for separation, decoration, environmental protection and reducing air pollution in parks and squares. They are also planted in boulevards and urban roads to improve traffic safety and reduce noise pollution. During the season growth, the pruning and trimming of these shrubs are necessary to improvement view, as well as embellish the urban green space. The purpose of this project was to implement a system that quickly and periodically trim the hedges with specific patterns and leading to provide a suitable and complementary replacement for labor. Because trimming requires a skilled labor that works with special tools and equipment, which caused low speed workang fatigue –because of carrying the heavy trimmer saws for a long time- but also heighten the risks due to the vehicles and existing traffic. The mechanism of this system was designed by attaching the mechanical part to the tractor's three point hitch, two frameworks were designed for vertical and horizontal movement of the trimmer system and help the initial positioning. For the trimming part, a hedge trimer mounted on a support plate was used which is easily able to move up and down by pulley and the metal wire mechanism. To adjust movement, two bearings with two axes were used. For trimming mechanism, two spools were used. The upper spool was driven by an engine. It was attached to the gearbox and it can rotate clockwise and counterclockwise. To have a smooth and consistent movement in up and down directions, another spool was mounted on the bottom of the frame. The engine speed was also controlled by the electronic system and depends to the desired model. To select the appropriate hedge trimer, it was necessary to measure the shear strength of the stems of the plants. Stem samples with three different diameters of ligustrum, oleander and euonymus were prepared and at three different speeds of 10, 20 and 40 mm / min were cut by Universal Testing Machine. The results showed that ligustrum shear energy was more than euonymus and euonymus more than oleander. The results showed that by reduced the stem diameter by 44%, cutting energy was reduced by 70% and by decreased the speed by 25%, the energy consumption for cutting was decreased by 62%. Needed for a hedge trimmer with a shear power of 3050 J/mm 2 for trimming the hedge of the width of 70 cm. Key words Trimming, shear strength, stem cutting, scissor mechanism, ligustrum.