Pruning evergreens tends to be done with a light hand as many are slow growing and the natural form can be marred for extended periods by overzealous pruning. According to Colorado State University, most evergreen species require little to no regular pruning at all. All evergreens, however, will benefit from the removal of dead and diseased foliage and branches. Light pruning to adjust size or shape can be done infrequently if necessary to prevent interference with surrounding structures.
Prune evergreens in the early spring before new growth becomes apparent so as not to disrupt the spring and summer growth cycle nor put stress on the plant.
Trim back discolored leaves, dead branches or any shrub tissues that appear to be suffering from disease. Cut branch by branch and do not shear off large swaths of tissue in one cut. Place the cut back only as far as needed to reach healthy foliage or wood and no further.
Cut back the perimeter branch tips of the shrub minimally as needed to clear a pathway or prevent conflict with other plants, utility boxes, buildings or other outdoor structures.
Pull the cuttings out of the shrub canopy and clear them up from the soil to keep the soil surface from becoming a breeding ground for pests and disease.