‘Tis the season that evergreens are on display. Not only as wreaths, swags, and holiday trees, but in our landscapes. As autumn leaves fade and fall, the evergreens that remain gain our attention and appreciation. Although evergreen conifers can be great assets to our gardens, some are more suitable than others.
Evergreen conifers
There are many types of evergreen conifers you’ll see in local landscapes. These include members of the pine family (Pinaceae):
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- cedars (Cedrus),
- firs/spruce (Abies, Picea),
- hemlocks (Tsuga),
- and pines (Pinus)
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the cypress family (Cupressaceae):
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- arborvitae (Thuja),
- Chamaecyparis,
- Cryptomeria,
- Cunninghamia,
- Hesperocyparis,
- junipers (Juniperus),
- and hybrids such as Leyland cypress (x Hesperotropsis leylandii)
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and the yew family (Taxaceae):
- Cephalotaxus,
- Taxus,
- and Torreya.
Identifying evergreens
If you admire a particular evergreen in the forest, a neighbor’s yard, or even a live holiday tree, the first thing to do is identify it. With evergreen conifers the “leaves” provide important clues:
- Members of the Pine and Yew families have needles—Yew family needles tend to be broader than pine family needles.
- Most members of the Cypress family have either awl-shaped leaves or scales.
Cones and bark offer other important clues to confirm conifer ID. See, below, for helpful sources.
Choosing evergreens for your landscape
Once you’ve identified interesting evergreens, decide where and how they will fit into your existing plantings.
General considerations. Evergreens provide shade and cover all year round, which can be a good thing, but before planting think about:
- mature size—both height and width
- impact on views
- shape—how will the shrub or tree change in shape over its lifetime and how much effort will it take to maintain it?
- avoiding a monoculture—planting several of the same plants—because if disease or pests attack even one, the planting may fail.
Insects, diseases, and other problems. Not all evergreens that can survive in our area are good choices —including some natives—even if they will fit your homesite.
- Some popular Cypress family choices— arborvitae, Japanese cedar (Cryptomeria japonica), and Leyland cypress—have many known problems (read more at: https://pdic.ces.ncsu.edu/decision-guide-for-cypress-problems/). Leyland cypress is considered so problematic it is not recommended for planting anywhere in North Carolina!
- In the Pine family, hemlocks need protection from hemlock woolly adelgids, and firs and spruce are subject to other insect and environmental problems, as are some pines (see details, below).
- Yews, too, have insect, disease, and siting issues to consider (links below).
What about choosing a live holiday tree? Many trees are sold live in containers or wrapped in burlap for planting outdoors after indoor display for the holidays. North Carolina Forestry specialists note that of the most common holiday trees sold live, only a few are adapted to mountain environments:
- white pine (Pinus strobus),
- Fraser fir (Abies fraseri),
- blue/Colorado spruce (Picea pungens),
- Norway spruce (Picea abies),
- and white spruce (Picea glauca).
Note that other live trees sold for the holidays—Arizona cypress (Hesperocyparis arizonica), and Virginia pine (Picea glauca)—are better suited to transplanting in Coastal and Piedmont regions of the state.
Unfortunately, even the mountain-adapted species have limited success planted in home landscapes. Fraser fir is often afflicted with balsam woolly adelgid. White pine and spruce trees do best in cooler sites, protected from winds. White pine does well in altitudes up to 3,000 feet; spruce species seem to do better at higher elevations; our only native spruce species, red spruce (Picea rubens), naturally occurs only above 4,500 feet!
Which native evergreens are good choices? Some native evergreen trees that do well in the mountains and are valuable to wildlife are:
- eastern red cedar (Juniperus virginiana), which provides cover for wildlife, fleshy fruit to eat, and is a host for butterfly larvae,
- shortleaf pine (Pinus echinate), which provides cover, seeds to eat, and is a host for butterfly larvae,
- white pine, which provides cover and seed,
- and loblolly pine (Pinus taeda), which provides cover and seed, and is a host for butterfly larvae.
Article written by Debbie Green, Extension Master GardenerSM Volunteer
For more information:
Identification:
Leaves:
https://www.trianglegardener.com/tips-to-identifying-conifers-in-the-landscape/
https://smallfarms.cornell.edu/2019/02/arent-they-all-just-pines-how-to-id-conifer-trees/
https://herbarium.ncsu.edu/tnc/vis_gymno.htm
Cones and bark: https://dnr.maryland.gov/wildlife/Documents/Basic_conifer_key.pdf
Evergreen conifer problems:
Overview: https://content.ces.ncsu.edu/insect-and-related-pests-of-shrubs/pests-of-conifers
Cypress family: https://pdic.ces.ncsu.edu/decision-guide-for-cypress-problems/
Pine family:
Pines: https://content.ces.ncsu.edu/pine-pest-management-calendar
Hemlocks: https://savehemlocksnc.org/info-for-landowners/landowner-treatment/
Blue/Colorado spruce: https://henderson.ces.ncsu.edu/2020/07/colorado-blue-spruce-issues/
Yew family:
https://www.uky.edu/Ag/Entomology/treepestguide/taxus.html
Live holiday trees: https://content.ces.ncsu.edu/selection-and-care-of-living-christmas-trees
Landscaping with native plants: https://content.ces.ncsu.edu/landscaping-for-wildlife-with-native-plants