This season I’ve had opportunities to work with gardeners incorporating evergreens into landscapes. In the past, conifers haven’t been that interesting to me, although I am awed by the majestic white pines in the woods behind my house and curious about eastern red cedars (Juniperus virginiana), which have sprouted where we’ve limited or stopped mowing.
I have lots of judgmental opinions about arborvitae lining property edges, a barrier of green that stands through the seasons. There must be more creative and aesthetically pleasing ways to create a fence than trees crowded branch to branch.
When browsing at garden centers — don’t we all do that? — I see the same cultivars of arborvitae, yews and juniper repeatedly, almost as if the Gymnosperm family were limited to the few that can be plopped against the foundation of a house and ignored. Once I dug in, I discovered many lovely and interesting evergreens and started to appreciate that, because of all the breeding, there are sizes and shapes that cover the most specific needs.
In landscape design, evergreens are said to provide “structure” to a garden. They hold it together by looking the same in all seasons, providing a backdrop for deciduous trees and the herbaceous layer. I get the concept but don’t agree that only evergreens can hold the space. Branch structure and the seed heads of dormant perennials and grasses can be equally beautiful during the dormant season and look intentional, too.
A database like conifers.org is a useful starting point for discovering evergreens native to the Northeast. After some searching, I’ve realized how few I’ve seen growing naturally. I need to get out more — and bring a tree identification guide.
An important caveat for planting evergreens is to consider how to protect them from the deer. Even the sharpest needles aren’t a deterrent when food is scarce. It’s also the reason that seedlings don’t make it in the forest.
I planted two northern white cedars (Thuja occidentalis) from one-gallon containers years ago and carefully fenced them. But after two winters when the snow was deep enough for the deer to reach them, they are now 15 feet tall but the lowest 4 feet are missing branches.
The challenge of placing a tree near the roadside is to make sure road crews don’t hack it during clearing. Smaragd (Thuja occidentalis) is on the shorter side, topping out at 12 feet. This one can be tricky, though, because it has a narrow, columnar form, rather than the fullness of other evergreens. I would complement it with shrubs that have a round shape and spiky blooming perennials.
The De Groot’s spire cultivar can grow up to 20 feet tall and is much fuller in shape, half as wide as it is tall when full size. It would look lovely with clusters of red twig dogwood and white flowering perennials to accentuate the blue-green foliage.
For an area that is larger and can accommodate a mix of hardwoods and evergreens, experiment with the spruce pine (Pinus virginiana), eastern red cedar and blue atlas cedar (Cedrus atlantica), which is going to be more tolerant of our winter temperatures. Add in a redbud (Cercis canadensis), a few gray birches (Betula populifolia) and a hardwood like an oak species, and there will be shade and beauty for everyone to enjoy, including wildlife and birds, in every season.
I can’t recommend any hemlocks (Tsuga spp.) because of the damage done by the hemlock woolly adelgid, a pest active during the winter that leaves a white powder on branches. It is widespread in the Hudson Valley; researchers are focusing on biocontrols, such as releasing predator beetles and flies to fight back.