Now is a good time, before new growth starts, to survey your landscape and decide what evergreens need pruning. Pruning evergreens helps to control size and shape and thins out the plant. It directs growth and reduces the threat of disease. You can easily see the new growth of this past summer and decide what needs to be trimmed or removed.
Evergreen plants can be divided into two broad categories: 1) Narrow leaf (needled) evergreens such as pines, junipers and yews, and 2) Broadleaf evergreens such as rhododendrons and hollies. The narrow leaf include many tree forms and are usually grown for their foliage only. They generally grow faster than broadleaf evergreens. Broadleaf evergreens include many shrub forms and are grown for their flowers and fruit as well as their foliage.
When to Prune – The best time for general pruning is in late winter or early spring (March or April) immediately before new growth resumes. Dead, diseased, and broken wood can be removed at any time of year. Generally, if you cut back an evergreen to the point where there is no green on a branch, that branch will die. Plants may be injured but seldom, if ever, are they killed by poorly timed pruning.
Pines: Prune in early spring; additional pruning may be done before new growth hardens. Make cuts just above needle whorls. Pines normally require little pruning.
Spruces and Firs: Prune in early spring. Cuts may be made at any point along the younger portions of the branches.
Juniper, camaecyparis and arborvitae: Prune in early spring, Can withstand relatively heavy pruning. You can occasionally prune lightly later in the season if necessary.
Yew and hemlock: Early spring is the best time for pruning, although occasional light pruning later in the season may be necessary.
Box evergreen, privet, barberry and pyracantha: These species grow rather rapidly. All will stand heavy pruning, which is best done in early spring. Because they are generally quite vigorous, additional trimming during the growing season may be advisable.
Hollies: These plants include both tree and shrub forms. American holly may be pruned in December.
When pruning American holly, always make the cut at a node, just above a lateral bud. Prune so as to maintain the natural shape. The shrubby Chinese and Japanese hollies can be more severely trimmed.
Purdue University Extension Service has an excellent publication on pruning, “HO-4-W Pruning Evergreen Trees and Shrubs.” You can go online and "Google" the title and publication #HO-4-W and it should be the first listing. You can also call the local Extension Office for a copy.
The Purdue University Cooperative Extension Service can be reached at 260-499-6334 in LaGrange County.