Evergreens bring an added dimension to the landscape in almost every climate. This is especially welcome during those long winter months when deciduous plants have lost their leaves. To be classified as an evergreen, a plant must hold its foliage throughout the entire year. Generally, evergreens grow best with little or no pruning. When they are grown in their natural form, they will be the strongest and healthiest. Good reasons to prune would be to remove damaged or dead branches, to shape young trees and shrubs or to thin excessive growth. Before you take your pruning shears out, take a few minutes to evaluate what is best for your evergreen. Have a clear goal before you start any pruning.

Are there different types of evergreens? Pines, firs, hemlocks, yews and spruce are the most common needle-leaved evergreens grown in our climate. Others evergreens such as junipers and arborvitae have scaly, needle-like structures. In our area, we are also able to grow a few broadleaf evergreens, such as rhododendrons and boxwood.

Does each type of evergreen need to be pruned differently? There are some important differences in how they grow that will effect how you care for them. For instance, needled evergreens put out one major push of growth each year in late spring/early summer. Yews have a strong growth period in late spring and often a smaller one in mid summer. Some scaly, needle-like evergreens, such as junipers and arborvitae may put on several growth spurts during the season.

Are there similarities, too? No matter what type of evergreen, almost all new growth will come from buds started the previous season. These are usually terminal buds, located at the ends of branches. Another common factor is that all evergreens are very reluctant to re-sprout from bare or old wood. Once you have opened up an area and can see the branches or trunk, it may not ever fill back in. Yews are an exception, often filling back in when pruned back severely.

What is the best way to prune broadleafs, such as rhododendrons? Broadleaf evergreens are handled the same as deciduous trees and shrubs. You can thin to control the height and size. On flowering broadleaf evergreens, prune right after they have bloomed. Rhododendrons will also profit from having the growing tips pinched back, encouraging side growth and better blooming. Korean boxwood can be lightly pruned at any time.

What is the best way to prune needled evergreens? To prune needled evergreens, remove about 1/3 - 1/2 of each new growth candle. ‘Candle’ is the term for the long, narrow growth shoots at the tips of branches. They are usually a soft, light green in color until they are fully expanded, when the needles begin to stiffen and develop a darker color. pinch right after the new growth has finished expanding, but before it has hardened off. In our area, this is usually in early June. If you need to take off more, prune out branches selectively, taking them back to where they meet another branch. Avoid removing lower branches unless they are diseased or damaged.

What would happen if I pruned off all of the candles? On most needled evergreens, candles represent all the new growth for that season, and removing them entirely will have several effects on your evergreen. It is much more difficult for the plant to initiate next year’s growth buds from the older, woody growth. If you prune off all the candles, you may greatly reduce how much foliage will be on the branches.

How should I prune my yews? Yews can be selectively pruned to thin and control size, or they can be sheared. Selective pruning should be done while the plant is dormant. Shearing yews for a more formal appearance will result in thicker growth on the outside of the shrub. To be kept full, sheared yews should be pruned twice a season, once after each growth spurt (late spring and again mid-summer).

How should I prune my junipers? Because they put on growth throughout most of the season, these plants can be selectively pruned almost any time. Again, remember they do not take well to shearing and are not likely to fill in bare spots.

What is best for my arborvitae? Of all the evergreens, arborvitae do the best sheared almost anytime, but never take off more than 2-3 inches from the outside. If the plant is way beyond the size you need, you can try selectively pruning out the longest branches.

Can I prune the leader on my evergreen tree? On evergreens with a central leader (main stem in the middle), it is best to avoid pruning it, if at all possible. Sometimes quickly growing varieties may develop a leader that looks way too long. If this happens, prune it back about a third. If it develops extra leaders, prune them out.

Why should I avoid pruning in August and September? The natural response to pruning is growth, and new growth initiated late in the growing season may not be winter hardy. In our climate, it is best to avoid any elective pruning from August until we have had a hard frost.

Are there any special tools for pruning evergreens? All you will need is a good pair of hand pruning shears. The best ones will be bypass pruners, with blades that pass by each other like a scissors, making a good, clean cut. Evergreen foliage will make the pruners sticky, so clean them frequently with alcohol. If you are shearing arborvitae, you may find a hedge shear easier and quicker to use, but don't be tempted to use it on anything but a hedge, since it does not allow you to make precise cuts.

Do I need to use a pruning sealer? Generally, pruning sealers tend to do more harm than good, and they look unattractive. The only exceptions are plants susceptible to disease transmission through open wounds and this is usually not a problem with evergreens.

Recommended Products
Felco Pruners
Various Other Hand Pruners
Loppers and Pole Pruners
Pruning Saws

Additional Bachman’s Information
Pruning Basics
Quick Pruning Tips
Pruning Deciduous Trees and Shrubs
Needle Drop in Evergreens
Fertilizing Trees and Shrubs
All About Watering

©Bachman's 2007