Evergreen trees and shrubs are usually most attractive and healthy when allowed to grow in their natural form. However, proper pruning is sometimes beneficial, artistically as well as physically.
If the plant is getting too large for its location, pruning usually is the solution. With spruces, firs and most pines, pruning must be done at a certain time and in a certain way or the results may be disastrous.
The only way to keep a pine tree small is to remove some of the new growth each year. This is also true of spruce and fir. Pine trees make all their above-ground growth within a few weeks each spring.
In the early stages the new pine growth will have candle-like growth at the top and ends of branches all over the tree. As the new growth matures, needles appear on the candles.
Use a knife to prune the pine after the new growth is almost completed. Cut the new shoots, or candles, to about an inch. Do it before the needles on the new shoots start to grow.
Pine, spruce and fir can be prune annually to slow increase in growth. Pruning should begin at an early age and be attended to regularly. One sudden shearing will not correct years of neglect.
Pine trees, spruces and firs do not have latent (dormant) buds in the old wood.If a branch is cut back to old wood and no side branches remain on the branch, no new shoots will develop and the branch will die back all the way to the trunk.
If these trees have already outgrown their location, transplant them if practical; otherwise use them for Christmas trees.
The lower branches of pines, firs, spruces and hemlocks should not be removed unless dead or diseased. With bare trunks, these trees look stiff and unnatural. If they are growing close together, nature will take care of the necessary pruning. If, however, a lower or excess branch must be removed, it can be done at any season.
Junipers need some pruning to keep them within bounds. Arborvitae and retinosporas are usually pruned to insure even growth or to create a more formal shape. Japanese yew, Canaert red cedar and Pfitzer juniper require regular trimming. Some yews may need severe pruning to remain compact.
Such pruning should be done regularly. If it is put off until the plant has outgrown its space, and is then beheaded and brought down to size, there is no way to conceal the butchery. If one anticipates the growth by two or three years, more subtle pruning can be done.