Seeming to prove that winter's cold has not caused all vegetation to perish, evergreens have long been a symbol of hope during the dark winter months, particularly among ancient cultures. Evergreens are the predominate vegetation in cold, mountainous regions where few other woody plants can survive. In urban and suburban yards, they provide winter interest when everything else in the landscape is bereft of leaves and color.
All evergreens have leaves that remain on the plant all year long, whether they are flat and broad, like a rhododendron, or skinny and spiked, like a pine. Evergreens grow as trees, bushes, small shrubs and prostrate groundcovers.
Evergreen varieties have evolved to grow in virtually all types of growing conditions, from hot and dry to cool and damp. One thing they all have in common is a preference for acidic soil. The addition of peat moss will help to lower the pH of the soil, and using pine needles as a mulch will also lower the soil's pH. Fertilizer specially formulated for acid-loving plants is another way to help lower the pH of the soil.
Evergreens are divided into two general classes: broad-leaf or conifer. The leaves of broad-leaf evergreens like holly, rhododendron and some varieties of ivy resemble the leaves of deciduous trees, but they remain on the plant year-round. Conifer evergreens are the traditional pine, spruce and fir trees and shrubs that grow needles rather than leaves and naturally grow into a pyramid shape.
Care and Culture
Perhaps one of the most carefree classes of plants and trees, evergreens generally require little pruning or fertilizing. They also dislike transplanting, especially once they've become established. Remove dead or diseased branches in June of each year and resist the temptation to remove the lower branches, especially if you live in an area with significant snowfall. Each branch is supported by the one beneath it, and if you remove the lower branches, the branches above it will succumb one by one, breaking under the weight of the snow.
Pests and Diseases
Although few pests and diseases affect most evergreens, they are bothered by some insects. Pine moths, beetles and needleminers affect pine and spruce varieties. Aphids, scale and spider mites can be bothersome on all types of evergreens. These maladies are all treatable with insecticidal sprays.