Many things come into play when pruning conifers. Is your pruning target the right plant for its space? If not, you may be forced to contort your plant into something unnatural for that species. So often we prune as a result of site limitations and other factors. I cannot stress the use of natives enough, along with their placement in an applicable environment for that plant’s requirements, rather than our own. Environmental requirements are more important to a plant’s survivability than are those of aesthetics. Therefore site selection is critical. So, how do we prune our precious evergreen friends?

Topiary squares and balls have their place, but creating these shapes is stressful on a plant’s physiology. Leaves generally cannot grow without a relationship with light. Sunlight, for which they hunger, is all powerful. Shearing evergreens forces them to grow leaves on their outer parameter only. This inhibits light reaching the plant’s interior and debilitates the tree’s ability to manufacture chlorophyll. The phenomenon of photosynthesis is the keystone of a plant’s well-being . Well then, how do we get this sunlight into our evergreens? Simple, let them grow into a shape or form most natural to that species, or prune them to simulate their most natural behavior. It’s called naturalized pruning. We reach into its branches, clip from deep within the plant, which enables us to thin and open its crown at the same time. Rule #2, take the most amount of wood possible with the fewest amounts of cuts. If you have two branches that are doing the job of one, remove the weakest lead or branch. The idea is to see into the plant while artfully helping it to look the most natural. Plants that respond to this with great vigor are, most hollies such as Nellie Stevens, Japanese varieties, blue holly and helleri, yews, junipers, boxwood, (especially English) and a few others. By opening these plants in this fashion, the plant begins to grow leaves on all its surfaces. The more leaves a plant has, the more sugar it can produce through photosynthesis, the more able the plant is to care for itself. Over several years, I have observed that the evergreens we prune every year or every other year are the one’s we rarely treat for mites, insects or diseases. Most species of evergreens can be pruned this way. However due to flowering, the timing of your pruning will be an issue.

While hollies and others mentioned are pruned in late winter early spring, there is a group that we will clip late spring, or after flowering. Not all, but most significantly flowering species are done this way. Some are, Rhododendron, mountain laurel, azaleas, pieris Japonica or Andromeda and of course Southern magnolia which most people prune after enjoying their late season flowers. Holy conifer, Shrubman! We forgot our needled friends.

Our needled evergreens are alike in some ways and not so in others, to their broadleaf relatives. Placement of spruce, fir, pines are critical. Quite simply they were not made to prune. They grow in a very distinct, genetic pattern and enjoy being in the open with “room to grow”. When allowed to do this they are magnificent. There are, however a few evergreens that do withstand good pruning and unlike spruce and a few others, will put on new growth. 

Cryptomeria, Leyland cypress, chamaecyparis and white pine prune very well. The first three conifers can be pruned the same way most deciduous trees are done. They can be thinned or reduced in size, always remembering to cut back to healthy laterals and “branch collars”. They should fill back in nicely during the next growing season. We will discuss more of that at a later date. White pines respond to pruning in a special way and should be done as one of your final early spring responsibilities. This type of reduction pruning will keep your pines fuller and more compact. It happens in April. After weeks of warm weather, you will begin to notice the “terminal” buds on your white pine have opened and are growing upward. They are not yet needles but instead look like a stalk or “candle” protruding from the end of each applicable branch. Stand by. When the candle is at full length, 2-3 inches, it will begin to open to produce the needles. At this time, cut one-half to two-thirds off of each candle. That’s right, just cut back the candle. This will stall the energy going to the end of the branch and in turn re-direct that energy to the side or lateral branches. This is a good way to keep a row of white pines as a hedge, but on the other hand is very labor intensive. If we need a hedge, let’s plant the right tree or shrub. Remember, it is usually easier and healthier to choose suitable plant material for the task, than to ask a large plant to be small.

I hope that gives you a place to start. There is one more thing to remember. All our evergreens are here for us to enjoy and serve a purpose. Think of that beautiful Nellie Stevens holly hedge that so affectionately surrounds and protects your backyard, not to mention the winter harborage for our goldfinches, kinglets and pine siskins. When we care for these shrubs, think of them not only as a weekend task but also as a canvas with your pruners as your brush. Shrubs truly are a work of art and will become more beautiful with age, if we will let them.