Evergreens or conifers are usually pruned only to remove dead, diseased or damaged wood. You can also prune them to encourage bushier growth, while maintaining their natural shape.
Unlike deciduous shrubs, conifers do not readily produce new shoots on old wood. This means that pruning should be limited to stems under two years of age. Only yews (Taxus spp.) and hemlocks (Tsuga spp.) tolerate more severe pruning.
Spruces (Picea spp.), pines (Pinus spp.) and firs (Abies spp.)
These evergreens should be pruned in late spring, before the needles on new shoots (candles) open. Use a hand pruner to cut the candles back by one- to two-thirds.
The tips of branches pruned after the needles are fully formed will turn yellow.
Cedars (Thuja spp.), false cypresses (Chamaecyparis spp.), junipers (Juniperus spp.), yews (Taxus spp.), larches (Larix spp.), microbiotas (Microbiota decussata) and hemlocks (Tsuga spp.)
These evergreens should be pruned when the new shoots are almost fully grown, around late June. You can also prune them until early September, except during extremely hot or dry spells.
Use a hand pruner to cut the new shoots back by one- to two-thirds.
Pruning the central leader
Never cut off the central leader on an evergreen that forms candles, or you will destroy its natural shape and weaken its structure. If there is a double leader, keep only the most upright one.
Scale-bearing evergreens, like cedars, junipers and false cypresses, often have several fairly weak leaders. Keep only the strongest one and remove the others.
A damaged or broken leader should be replaced with a vigorous, well-located lateral branch. The technique is the same as for deciduous trees.