An evergreen shrub hardy in U.S. Department of Agriculture plant hardiness zones 4 through 9, Irish juniper (Juniperus communis) grows narrow and tall, reaching 5 to 15 feet tall and 2 to 4 feet wide. Though pruning is not always essential to maintain its form and size, it will not help fine tune its contour, and it keeps the shrub healthy by removing diseased and insect-infected limbs.
Cut Irish juniper branches in early spring to form the tree and also to remove unwanted, wayward growth. Snip the branches to the desired lengths, making sharp cuts so you do not damage the stems. Prune again in late summer or early fall if desired.
Eliminate insect-infested stems instantly and discard. Juniper webworms, as an example, can be a problem for Irish junipers. If they are so numerous that you can’t physically remove them to keep them under control, then you need to cut off the infested branches.
Prune stems inflicted with a disease, such as juniper twig blight. Cut the branches back to fit sections and discard the prunings.