Pruning Conifers for Health
Dead, diseased, or damaged branches should be removed when the problem arises
One reason to like conifers is that they generally require little pruning. Still, it is occasionally necessary to prune these plants to improve appearance and/or to prevent future problems. It’s important to remember though, conifers are not like other woody plants. They respond differently to pruning, often not resprouting new growth if you make cuts in the wrong location. Think of them as beautiful, but finicky.
In this video, Bert Cregg, an associate professor of horticulture and forestry at Michigan State University, demonstrates how to prune a common juniper (Juniperus communis, Zones 3–9) that has suffered damage either from winter weather or a fungus.
Step 1: Prune out any damage
The damaged shoots are easy to spot (generally brown or discolored in some way) and should be pruned all the way back to the healthy part of the plant, even if that is the base, because junipers will not grow from old wood.
Step 2: Make heading cuts to improve habit
At times it may be desirable to prune a conifer to improve its shape and fullness, even if it has no damaged shoots. Pruning the plant for this purpose involves making heading back cuts of longer shoots in order to reduce the size and increase the fullness. Cregg recommends cutting back to a branch union. As long as foliage is growing there, pruning will create new growth points and make the growth fuller.
The methods outlined in this video, although demonstrated on a common juniper, can also be applied to pruning other evergreen conifers such as arborvitae (Thuja spp. and cvs., Zones 5–9), false cypress (Chamaecyparis spp. and cvs., Zones 4–9), yews (Taxus spp. and cvs., Zones 4–8), pines (Pinus spp. and cvs., Zones 2–9), hemlocks (Tsuga spp. and cvs., Zones 3–8), firs (Abies spp. and cvs., 3–7), and spruces (Picea spp. and cvs., Zones 2–7).
Pruning of this nature can be done any time the problem arises.