Level evergreens perform best as hedge shrub, accenting the front of your house or providing privacy from the street. To keep a hedge level, gardeners should trim regularly; to keep an evergreen hedge healthy, gardeners should trim at a slight angle rather than a flat line. Begin pruning your evergreen shrubs in the late winter to early spring and trim as often as needed throughout the growing season to maintain your desired shrub height and shape.
Step back and inspect your evergreen hedge, noting any low-growing or wayward branches that detract from the evergreen's form. Prune away these branches using pruning shears. Cut them off at the base, but do not cut into the trunk or originating branch.
Clip off branches that are wounded, discolored or bear growths, since these are unhealthy. Also trim back branches that compress other branches, since this growth will cause limb damage if not removed.
Shape the top of the evergreen into a straight line or rounded dome. While straight tops are more level, they accumulate snow and ice and can get damaged under heavy loads. Texas A & M recommends rounded tops for evergreen hedges for this reason, and because they require less frequent trimming. Work with hedge clippers and cut across the top of the evergreen hedge from one side to the other.
Step back and examine your work. Adjust any imperfections until the top of your evergreen makes an even dome with no high points or a flat, straight line.
Shear the sides of the evergreen into a slight pyramid shape. Work with hedge clippers and cut the evergreen back so that the base of the shrub is wider than the top. If you level the entire side of the shrub, the bottom portion will receive excess shade and will grow poorly. Cutting it at a slight angle allows sunlight to reach all branches.
Trim your hedge again in this manner throughout the season to keep it at the desired size.