Juniper shrubs vary greatly in size, but all are pruned following the same basic principles. Juniper grows a large "dead zone" in the center of the plant, which contains no foliage. Each year the plant gets bushier as the dead zone increases. Avoiding this dead zone while making the correct pruning cuts can be tricky for beginning gardeners at first. Prune juniper annually to maintain a nice size and shape and keep the plant healthy. Always prune in the late spring once frost danger has passed.
Check over the branches of your juniper shrub for signs of dead, diseased or damaged branches. Diseased or damaged branches bear physical discoloration, wounding or other markings. Dead branches feel brittle when touched and will not have foliage.
Prepare a 1:10 solution of bleach:water in a bucket. Place your pruning tools in the bucket.
Cut off all dead, diseased and damaged wood at its base. If only the tip of the wood is damaged, cut back to a Y-intersection that is healthy. In between every cut of this bad wood, dip your pruning tools back in the bleach solution to sanitize them. Once you've removed all unhealthy wood, dispose of it in the garbage bin and throw away your bleach solution.
Trim back long branches on your juniper by cutting back to a Y-intersection or a node. Never trim so far back that the branch has no more green growth on it, since it cannot regrow from plain wood. Also, avoid cutting into the dead zone at the center of the juniper unless you plan to remove the entire branch.
Remove large branches to thin out the juniper by cutting them off at the base. Select only branches you can remove without leaving a large gap in the plant; branches covered by other growth are good choices to remove.