"Conifer" is an arboricultural term meaning, literally, a cone-bearer (such English words as "refer" and "aquifer" also use the FER Latin root, meaning "to bear"). Trees and shrubs that fall into this category reproduce by forming a cone rather than a flower as a container for their seeds. It is this fact regarding reproduction that points us to the difference between evergreens and conifers. The corresponding adjective is "coniferous."
Most conifers are evergreens, but not all of them are.
Examples of conifers include the following evergreens:
- Canadian hemlock trees (Tsuga canadensis)
- Hinoki cypress trees (Chamaecyparis obtusa)
- Colorado blue spruce trees (Picea pungens)
- Japanese dwarf pine trees (Pinus parviflora 'Arnold Arboretum Dwarf')
- Umbrella pine trees (Sciadopitys verticillata)
- False cypress shrubs (Chamaecyparis pisifera)
- Arborvitae shrubs (Thuja spp.)
While there is overlap between the two botanical classifications, "conifer" and "evergreen," their definitions actually address separate issues. The former pertains to means of reproduction (the cone); the latter, by contrast, pertains to the nature of a tree's leaves (or "needles").
Perhaps the best-known example of the fact that not all conifers are evergreens is the larch tree (Larix laricina), also known as the "tamarack" tree. In summer, tamarack looks like it would be one of the evergreens, because it bears green needles. But this conifer is a deciduous tree. It even bears fall foliage, as the needles turn yellow in autumn.
Likewise, not all evergreens are conifers. Numerous broadleaf evergreens are not conifers because they reproduce via flowers, not cones; examples include:
- Holly shrubs (most Ilex spp.; but winterberry holly, Ilex verticillata, is deciduous)
- Azalea shrubs (Rhododendron spp.)
- Boxwood shrubs (Buxus spp.)
- Mountain laurel shrubs (Kalmia latifolia)
- Sheep laurel shrubs (Kalmia angustifolia)
- Andromeda shrubs (Pieris japonica)
Beginners often become confused by these terms and end up asking the wrong questions. For example, you will sometimes hear someone wondering whether such and such a tree is deciduous or a conifer, as if it had to be one or the other. But this is the wrong contrast to draw. The difference the person truly has in mind is between "deciduous" and "evergreen," where the issue is whether or not a plant's leaves fall from its branches every autumn.
Not All Cones Are Recognizable (to Novices) as Cones
Some trees and shrubs that you may not think of as being conifers actually are. Not all cones have the appearance of a classic cone, such as the spruce cone. Examples include:
- Maidenhair trees (Ginkgo biloba): What people think of as the messy "fruit" is really a cone.
- Juniper shrubs (Juniperus spp.): What look like blue berries to the average person are actually cones.
- Yew trees and shrubs (Taxus spp.): What appear to be red berries are really fleshy cones called "arils."
- Arborvitae shrubs: What gardeners sometimes worry about as yellowish-green "growths" on these bushes are actually cones. The cones are a more attractive blue on the Blue Cone cultivar (Thuja orientalis 'Blue Cone').
Pros and Cons of Growing Conifers and Evergreens
The wisdom (or lack thereof) of selecting this type of plant for your yard depends on factors such as:
- The amount of landscape maintenance you are willing to do
- The qualities of the specific plant you will be growing
- Where the tree will be planted
- Whether or not you enjoy crafts
- Whether or not you need year-round privacy in the yard
Conifers with large cones, such as eastern white pine trees (Pinus strobus), can be some of the messiest trees to grow, creating more landscape maintenance than some people care to engage in. Furthermore, it is a double whammy if you plant such a tree in a spot near where you park your car. Not only will you be raking cones off your driveway, but you will also be cleaning pine pitch off your windshield (plus those needles have a way of getting under your vehicle's front hood and taking up residence there).
But the cones of a conifer such as Blue Pfitzer juniper shrub (Juniperus chinensis 'Pfitzeriana Glauca') are too small to be messy. Even the types with larger cones are valued by some people. They are collected by crafts enthusiasts to make, for example, kissing balls, wreaths, or various other natural Christmas decorations.
Evergreen trees and shrubs are also useful for people seeking living privacy walls all year long. You can get away with a hedge of deciduous trees or shrubs if all you need is privacy for the summer (as when Northerners grow screen plants around swimming pools), but those plants will be useless if you need privacy in winter, too. Whether you are looking for a plant to cast shade, offer privacy, or make a landscape-design statement, you will value the steadiness of evergreens.
How to Properly Identify Common Conifer Trees. MSU Extension Website