The western cedar or Thuja plicata is also called great western arborvitae, western red cedar, canoe cedar, Pacific red cedar, shinglewood, and giant red cedar. This beautiful evergreen can attain heights of 50 to 60 feet and spread as much as 15 to 20 feet. In your landscape design it can be used as a windbreak, hedge or screen. The western cedar is hardy in zones 5 through 9 and requires very little pruning. Objectives of pruning: remove damaged or diseased branches, shear to maintain size and space in your landscape, and reshape for safety reasons (walkways, structures, roofs).
Immediately remove any damaged or diseased branches. Make a clean cut; this will allow the tree to heal properly. This type of pruning can be performed any time of year. Do not put any diseased material in your compost bin. Be sure to disinfect your cutting blades by dipping them in rugging alcohol or a bleach solution.
Shear the western red cedar in the early spring if you are using it as a hedge, screen, or windbreak. Light shearing will maintain the tree's shape and appearance and encourage new growth to sprout from the old wood.
View your tree from all angles to make sure it's not interfering with walkways or rubbing against the side or roof of your home or other structure. Over time, rubbing branches may cause damage that can lead to a leaky roof.
Cut off or shear any branches that present a safety hazard. This should be done in the early spring or late fall.