Evergreen Facts
A Few Evergreen Facts For Your Landscape Planning
It's not uncommon in researching evergreen facts to confine the subject to conifers. The terms conifer and evergreen are often used synonymously, limiting the scope of any discussion of evergreens to familiar conifers such as fir, pine, and spruce. Conifer means cone bearing, but the vast majority of evergreen trees, plants and shrubs are not cone bearing.
In tropical regions, much of the vegetation is evergreen. In more temperate climates, and in some colder climates, you will find a large variety of broad leafed evergreens, rhododendrons, azaleas, and holly being prime examples. Evergreen refers to any tree or shrub which does not completely lose its foliage during any period of the year, as opposed to deciduous trees and shrubs which do.
Here are a few quick evergreen facts that can be helpful if you have, or are planning to have, these plants in your garden. For one thing, watering requirements can differ significantly from plant to plant. Many of the smaller broad leafed evergreens require more frequent watering, while the larger conifers can easily survive dry periods due to their deeper root systems. Bear in mind however, that during prolonged dry periods, or periods of drought, conifers may become stressed and weakened. The trees will not necessarily die from lack of water, but become more susceptible to various diseases, or attacks from insects. Mulching, occurring naturally in the forests, will benefit evergreens in the garden by keeping root systems cool and conserving moisture.
Evergreens are for the most part, sun loving plants. In some tropical forests, few plants grow at ground level, as the foliage from the trees forms a canopy, placing the ground below in perpetual shade. In colder climates, among the conifers, this can sometimes also happen. Lack of sunlight discourages growth of seedlings, and a majority of trees, though growing fairly high, are spindly with branches only near the tops. In the garden, in places where there is not significant competition with other plants, evergreens will do quite well, even in partial shade or filtered sunlight.
Most conifers are evergreens, one notable exception being the Western larch, also called the Tamarack, which sheds its needles each fall. The other conifers shed their needles as well, usually in the fall and winter, but not all at once. The Ponderosa pine for example, will drop needles from the interior segments of its branches once the needles are around four years old. The needles at the ends of the branches are always the newer needles, and as the tree ages it becomes devoid of needles over most of the length of each branch.
The life span of needles on evergreens varies from species to species, in some cases approaching 20 years. The life span of Bristlecone pine needles may reach thirty years. The story of the Bristlecone pine is one of the more intriguing evergreen facts. These pines, of which there are three types in the United States, the Rocky Mountains Bristlecone, the Great Basin Bristlecone, and the Foxtail, are among the oldest, if not the oldest, living things on the face of the earth. Bristlecone pines have been known to have a life span of up to 5,000 years. This fact is even more amazing, considering that these pines often are found at higher elevations and are subject to harsh weather conditions.
Pine trees are among most familiar of the evergreen trees in the United States. The more common varieties are the Ponderosa pine, White pine, and Lodgepole pine. There are numerous varieties of smaller pine trees and shrubs, popular in gardens and landscaping. Pines generally thrive in a drier, almost arid climate, and like most conifers are extremely hardy where severe winters are common.
Fir is perhaps the most common conifer, and there are a number of varieties including Douglas fir, Balsam fir, and Noble fir, all popular in the garden, and all popular choices as Christmas trees. Other evergreens, along with fir, which are particularly in evidence in the Boreal, or colder regions, are spruce and hemlock. One of the reasons that so many of our evergreen forested areas lie in colder climates, is that the soil temperature is often too cold to enable decay, and therefore is not favorable for the growth of competing plants.
While the above evergreen facts may or may not help in deciding specifically what are the best choices in your garden, it may be helpful to know that the variety of evergreens is large indeed, as are your choices.