Here’s a good article on pruning pines from the Garden Editors at Better Homes & Gardens.
Although they all fall under the category of ‘evergreen,’ different varieties and species have different pruning needs and techniques. Here’s your guide to pruning different types of evergreens.
Evergreens are great plants for creating dense, green hedges and landscape shrubs. While they provide reliable color throughout the seasons, their evergreen nature makes dead, brown branches especially obvious. Unhappy evergreens may also appear scraggly and thin and need some shaping and training to fill in nicely. Here’s how to prune the most common types of evergreens.
While there are many types of pine, the technique for pruning pine trees and shrubs is the same. You can influence shape and ensure denser growth in spring by using your fingers to break off young pine tips at the halfway point. Avoid cutting off tips or branches.
Spruce and Fir
Spruces and firs have shorter, denser needles on their branches. Prune branches and young tips in spring to gently shape the tree. Shear again in late spring, if desired, after new growth has expanded.
Yews have flat, shiny needles and often have berries. To correct size or shape, prune in late winter. To create formal shapes, shear in spring after new growth has developed, and repeat in summer.
Junipers grow densely and have fragrant needles and berries. Prune in late winter before new growth appears to affect the evergreen’s natural shape. Do not prune back to brown, bare branches; regrowth there is unlikely.
Boxwoods are especially popular as topiaries and hedges. Use pruners to maintain shapes in late spring and again in late summer. Motorized trimmers can be used but will leave brown edges on leaves for a few weeks after shearing.