In order to prune pine shrubs or trees, you will need the following: pruning sheers. Conifers can be pruned, whenever they aren't growing. Pruning when a plant is actively growing will retard the growth. Therefore, if you need to restrict the height of a tree or shrub, then you would prune it, when it is in active phase. New bud formation will begin at the point where you trim. Future trimming should be done where new bud growth is found. Pinching is a technique that can also be used. Simply pinch and hold a tip for several seconds, which is an effective non-cutting method to restrict growth.