The Hidden Benefits of Evergreens
by Rob Sproule
They’re big. They’re foolproof. They kill the grass. But what else do you know about evergreens? How about that they can reduce your gas bill and keep bug-eating birds around? Let’s dig deeper:
“A tree with strong roots laughs at storms.”
– Malay Proverb
Okay, evergreens aren’t the sexist gardening topic. They’ll usually just “there”. But they’re so much more than ornamental. Did you know their other benefits?
We’ve heard about how big canopy trees, like Elms and Willows, help shade and cool homes against the summer sun. But what about winter? We get cold. Very cold. Winter winds pull the heat from our houses’ bones and makes our furnaces work overtime. Bring on the gas bills.
Plant evergreens to block the prevailing winds (which typically come from the North/ Northwest). You’ll want them close enough to the house to be an effective block, but not too close that the roots become an issue (15-20 feet for large trees). In northern climates it’s best to keep evergreens on the northern side of your home and deciduous trees to the south. A towering spruce on the south will block the winter sunlight that would otherwise warm your home. A maple or elm will let sunlight through in winter but shade you in summer.
I love deciduous trees to keep the neighbours from peeping on garden parties and lingering evenings on the patio. But what about winter? Just because the leaves are down doesn’t mean I want to keep my blinds closed. Evergreens shield 12 months/ year. If your windows are perilously exposed to your neighbours (ie. newer housing developments), some columnar evergreens, like junipers or cedars, will block the lookie-loos and take up very little space in return.
Homeowners are realizing that spraying chemicals on their yards is making things worse in the long run. It’s killing predators and creating vacuums for opportunistic pests to thrive. Natural yards, with healthy predator populations to prevent pest populations from spiking, are the path forward. But to stay in your yard, your predators need their own protection.
Evergreens help sustain populations of birds and other larger critters, which maintains the balance of your backyard ecosystem. Animals shelter from winter winds in the branches and huddle out of reach of hawks and other predators. Allowing large evergreen boughs to grow close to the ground gives even more protection. If you give your spruce the “poodle” look of pruning the first 6-8′ of branches, you’re losing a lot of the biodiversity that the tree would have brought (and your grass isn’t going to grow under it, anyway).
Trees are the Earth’s lungs, removing carbon dioxide and other pollutants and replacing with oxygen. In the summer, we look to our trees to guard our yards against the smog hanging on the horizon. But winter, when the leaves are fallen, is actually the worst time for airborne pollution. The power plants are working overtime to meet the demand for heat, and cold air forms a barrier that blocks pollutants from dispersing up into the atmosphere.
Barren branches don’t help air quality, but needles do. Evergreens clean your yard’s air 12 months / year. They won’t remove all the pollution, but they’ll help. Ever wonder why so many household cleaners smell like pine? Pine scent, along with other evergreens, contain oils that make their surroundings smell fresher.