- January 15, 2016
An evergreen is a plant that has leaves throughout the year. Deciduous plants, on the other hand, completely lose their foliage for part of the year, usually during the winter or dry season (depending on location). There are many different kinds of evergreen plants, both trees and shrubs; and, they have important roles to play in landscaping–from aesthetic to ecological. Read on to learn more about how and why to include evergreens in your landscaping.
Most species of conifers are evergreen (e.g., hemlock, blue spruce, red cedar, and white/scots/jack pine); but, this is not true for all species, such as the larch (Larix Occidentalis) pictured above in full Fall color as they prepare to drop their deciduous needles (yes, “deciduous needles” — pretty cool huh?).
Evergreens also include several broadleaved plants like some species of oak (Quercus agrifolia pictured above), American holly (Ilex Opaca), and many from places where there is no frost, like eucalyptus.
Trees and Their Leaves
Flummoxed by the conifer that loses its leaves? This handy chart shows you how to talk about trees like a pro.
- You can have broadleaved deciduous trees (upper lefthand corner in the graphic)–they lose their leaves for a portion of the year, and have large flat leaves–and you are likely very familiar with them (think maples, sycamores, ash).
- You can also have broadleaved evergreens (upper righthand corner in the graphic)–they have the same big leaves, but don’t lose their leaves on a regular basis–you likely know a few of these as well (holly, eucalyptus).
- Then there are coniferous evergreens (lower righthand corner in the graphic)–which have needles instead of big, flat leaves, and retain them year round–these are also familiar to you (think pines, firs, redwoods).
- The last and oddest are the coniferous deciduous trees (lower lefthand corner in the graphic)–these also have needles, but shed them for part of the year, often in Fall. You may have never seen, or noticed, a Larch tree before, but it is the prototypical example of this kind of tree, and looks like a coniferous tree in the summer when it has its green needles but then turns to a bright yellow-orange as its needles prepare to fall.
Now, go quiz your friends, you tree-guru you.
The Latin binomial term sempervirens (literally, “always green”) refers to the evergreen nature of the plant, for instance: Acer sempervirens (a maple), Cupressus sempervirens (a cypress), Solidago sempervirens (a goldenrod), Lonicera sempervirens (a honeysuckle), Sequoia sempervirens (a sequoia), Ulmus parvifolia ‘Sempervirens’ (an elm).
Evergreens can be important landscape elements for birds. When the temps drop and the snow flies, birds need thermal cover—that is, a place to get out of the cold and wind. Even in warmer climates, an unusually cool night can send birds looking for a place to get warm. But in January and February, with no leaves on deciduous trees, shelter can be harder to come by.
You can give birds a place to hide from the cold by adding an evergreen element to your site. Birds naturally seek winter cover in evergreen trees, which have dense needles that offer protection from precipitation and wind. You can see in the image above just how much an evergreen stands out in a sea of leafless deciduous trees.
The image above was taken on a windy -31°C day. The Chickadee is sheltering in this evergreen whose leaves help to break the wind. Without the tree, it would be more exposed. Some research has found that the higher the ratio of evergreens to deciduous trees in a yard, the greater the diversity of native birds found thereopen_in_new.
Birds aren’t the only animals to use evergreens for shelter during the cold months. The mule deer above is hunkered down amongst some Wyoming sagebrush (Artemisia tridentata ssp. wyomingensis), which acts as both shelter and food in the long northern winter.
Midwinter is an excellent time to head outside and assess your site’s evergreen availability. Go ahead, take a walk outside and see what still has leaves. How many trees? Shrubs? Vines? Based on research, we know evergreens tend to makeup a smaller percentage of a site’s available woody species than deciduous trees. This may or may not be true at your site (you can let us know with a comment, or better yet, a link to your habitat map!).
After you’ve assessed your site it is time to figure out if you want to add an evergreen (or evergreens). Besides being shelter for animals, evergreens can add to the overall look and feel of a location–taking it from sparse and drab, to rich and full–especially in the winter months.
Love the plants in the image above? Us too. The deciduous plant with the stunning yellow branches is a yellow twig dogwood (Cornus sericea ‘Flaviramea’. ‘Flaviramea’ is a yellow cultivar of the North American native shrub Cornus sericea, commonly called red-osier dogwood (PS – it is also a standout in the fall – see image below).
But, what to choose; and, where to put it? First, you need to get a rough sense for the space that you want to fill. Your habitat map can help you do this (what? You don’t have one yet? Read here to get you started), by giving you a sense of the total area in your site, and where the gaps are.
Evergreens come in all kinds of sizes–there are low spreading evergreens like Kinnikinnick (Arctostaphylos uva-ursi), tall, narrow evergreens like Eastern Redcedar (Juniperus virginiana), medium-high, wide evergreens like the green-leafed manzanita pictured above (Arctostaphylos patula) and large evergreen trees like the short-leaved pine (Pinus echinata).
You may want to block the wind (choose plants that are tall, and plant them clustered together or in a line). You may want to ensure you still have that view of the hills yonder (choose a low-growing plant that won’t grow to block the view). You might like to build volume in your landscaping by stacking evergreen species; tall trees in the back, medium height shrubs in the middle, and some low-growing–like common juniper (Juniperus communis) up front.
Another design tidbit: Consider creating a winter sun “trap” with evergreens planted on the northerly side of a site. In the short, dark days of winter they will have the effect of catching the, sometimes rare, sun rays coming in low from the southern sky and reflecting them back into your site, illuminating your home and the rest of your landscaping in a warm glow.
You’ll also need to be sure that the species or varieties you are considering can grow vigorously in the climate and site conditions of your property. One way to do this is to visit the Lady Bird Johnson Native Plant Finder page. There, using the combination search, you can set the characteristics of the plant you are looking for (say, Iowa, evergreen, 3-6 feet tall, shade) and it will list native plants that are a match. It will take a little bit of sleuthing to find the right plant, but what better way to spend winter months?
Another consideration you might want to take into account when choosing evergreens is whether or not they are a food source for wildlife. Some great choices if you want berry-producing evergreens are Eastern red cedar (Juniperus virginiana) (loved by Cedar Waxwings–the bird featured in the header image for this article and by bluebirds – as pictured above). This plant has some of the most winter persistent berries, meaning they last deep into the winter months when animals are running low on other food sources.
Spruces (Picea species) are another good choice, with seed-bearing cones that attract crossbills and other seed-eaters in fall and winter. Migrating warblers will search spruce trees for insects in spring, because evergreen needles are a good source of insects at that time of year.
Northern bayberry (Morella pensylvanica) is only semi-evergreen, but it is a nice shrub that produces fragrant, waxy, silver-gray berries, which stay on the plant year-round in some places and are used by Tree Swallows (especially wintering ones), Gray Catbirds, and bluebirds.