Lush evergreen juniper plants are known for their hardiness as much as for their vigorous spreading. To keep your plants under control, you'll need to trim juniper bushes in the early spring each year, removing old, dead growth and leaving behind new buds and green leaves. As you trim, your goal is not to cut back the entire plant, but to prune away excess and dead limbs while leaving behind a natural look.
Determine where the boundaries of the plant will be, whether you want to keep the plant from rubbing a nearby wall, draping over a raised bed or extending onto a walkway. Keep this boundary in mind as you work.
Cut back the tips of the green upper growth that fall beyond the boundary that aren't yet woody. As you cut, this should expose the lower growth to light and you should be able to see dead wood and brown needles closer along the ground surface or tucked inside the bush.
Single out an older, brown limb and untangle it with your hands so you can locate where it branches closer in toward the plant. Cut the old limb from the plant just after a branching so the newer wood left behind will mask the clipped edge of the limb.
Continue to cut away older, dying branches as you see them. As you work, the shape of the juniper may change slightly as other branches are shifted, so repeat Step 2 as needed.
Use a pruning saw if necessary as some of the wood can be quite thick and too strong for hand pruners. This is especially true if the plant hasn't been pruned in a while.
Continue to trim upper tips and prune away hidden dying limbs until the plant is the size you need it to be and it has a natural look. You don't want your plant to look like a buzz saw went passed it, so there should be light irregularities of the length of green limbs that remain rather than a clean slice across the plant body.