Pruning Evergreens
Evergreens come in an unlimited number of sizes and shapes. If the right evergreen is selected to fit the assigned space, minimum pruning is required. However, if pruning is necessary, the American Conifer Society makes the following recommendations:
Yews & Hemlocks
Easiest to control are yews and hemlocks. Both have abundant buds on both old and new wood that develop into twigs when the cut is above the bud. Thus, they can be sheared and not permanently harmed so they can be used as hedges. The leaves tolerate some shade so they grow well on the inside of the plant and hence the plant can be made dense by shearing or pruning. Pruning just before new spring growth allows the pruning cuts to be covered with new growth very rapidly to get away from the "just sheared look".
Firs, Cedars, Spruce & Douglas Firs
Next easiest to control are the firs, cedars, spruce, and douglas firs. These have easily identified buds along the current season's growth and sometimes on the stem of the previous year's growth. Size can be controlled at any time by pruning back to a bud or live twig. For a formal shape, they can be pruned or sheared when the current season's growth is soft (not woody). Their leaves are somewhat shade tolerant so pruning or shearing has the potential for making a dense plant.
Pines
More care must be taken with pines. When pruning pines one must be aware of their lack of buds along the stem and that buds are only at the tip of current season's growth. Thus, pruning at most times of the year must be done carefully or shape will be lost. The time to prune pines is in the spring when growth is soft, a candle (the expanding buds) can be cut or pinched before the needles are fully elongated and buds will develop from needle fascicles below the cut. Early summer pruning or "candling" will produce a compact plant.
Difficult Evergreens
The group most difficult to prune and control their size and the junipers, arborvitaes, and falsecypress (Chamaecyparis). In this group, buds are present only where there are green leaves; a branch cut back to a non-leafy region will not form new foliage. Thus cutting or shearing to the brown inner part results in an unsightly scar that may not be covered for many years if ever. The naked or brown interior is the result of the fact that this group's foliage is intolerant of shade and therefore the interior leaves die. If they are sheared, it should be done with care and only when they are actively growing in the spring. This group of plants ends up being a thin "shell" of green growth over a zone of twigs and limbs with no leaves and no potential for development of buds. Care must be taken not to open this thin "shell" during pruning.
Yews & Hemlocks
Easiest to control are yews and hemlocks. Both have abundant buds on both old and new wood that develop into twigs when the cut is above the bud. Thus, they can be sheared and not permanently harmed so they can be used as hedges. The leaves tolerate some shade so they grow well on the inside of the plant and hence the plant can be made dense by shearing or pruning. Pruning just before new spring growth allows the pruning cuts to be covered with new growth very rapidly to get away from the "just sheared look".
Firs, Cedars, Spruce & Douglas Firs
Next easiest to control are the firs, cedars, spruce, and douglas firs. These have easily identified buds along the current season's growth and sometimes on the stem of the previous year's growth. Size can be controlled at any time by pruning back to a bud or live twig. For a formal shape, they can be pruned or sheared when the current season's growth is soft (not woody). Their leaves are somewhat shade tolerant so pruning or shearing has the potential for making a dense plant.
Pines
More care must be taken with pines. When pruning pines one must be aware of their lack of buds along the stem and that buds are only at the tip of current season's growth. Thus, pruning at most times of the year must be done carefully or shape will be lost. The time to prune pines is in the spring when growth is soft, a candle (the expanding buds) can be cut or pinched before the needles are fully elongated and buds will develop from needle fascicles below the cut. Early summer pruning or "candling" will produce a compact plant.
Difficult Evergreens
The group most difficult to prune and control their size and the junipers, arborvitaes, and falsecypress (Chamaecyparis). In this group, buds are present only where there are green leaves; a branch cut back to a non-leafy region will not form new foliage. Thus cutting or shearing to the brown inner part results in an unsightly scar that may not be covered for many years if ever. The naked or brown interior is the result of the fact that this group's foliage is intolerant of shade and therefore the interior leaves die. If they are sheared, it should be done with care and only when they are actively growing in the spring. This group of plants ends up being a thin "shell" of green growth over a zone of twigs and limbs with no leaves and no potential for development of buds. Care must be taken not to open this thin "shell" during pruning.