Shaping in Early Years
Now for new hedges you will only want to shape them generally during their first season of growth. Do this using a pair of pruning shears and cut them down to a height of about 6 inches. At the end of the first season check the height and in the following spring you will need to do more shaping. You will want to trim them down to about half of their current size without needing too much of a focus on symmetry before they blossom. During their second season of growth you can also shape the sides lightly. Do this using a large pair of shears and trim any growth that is sticking out from the side. Focus mainly on the largely devian branches and leaves and avoid excessive trimming. At the start of the third growing season repeat this process although with greater shaping on the sides.
Shaping Adult Hedges
First thing you want to do with adult hedges is prepare them. Using stakes the same height as you want your hedge to be and a piece of string tied between them for a guide, use an electric trimmer to trim them down to size moving parallel to the string. Be very careful to make sure that the top of the hedge is level all over. Now you will want to prepare the hedges to be shaped along their width. Using the same stakes place them along the width of the plant and use this as a rough guide on where to cut to remove any growth that falls outside the area marked by the stakes.