When it comes to planting, trees can be tough, but they’re not invincible. That’s why timing is key.Alfo Medeiros/Pexels/iStockPhoto / Getty Images
Trees and shrubs are magical. They provide sustenance and shelter to birds, mammals and invertebrates, all while creating their own food almost literally out of thin air. And they play a vital role in the planet’s carbon cycle, sequestering carbon in their bodies and the soil as they release oxygen into the atmosphere.
When it comes to us, their role becomes even more essential. They offer privacy and shade, filter pollution, reduce surrounding temperatures and help block sound, says Janet McKay, the founder and executive director of Toronto non-profit LEAF (Local Enhancement and Appreciation of Forests). Trees and shrubs also support climate resilience. They play a key role in stormwater management, she adds, slowing rainfall’s movement into storm drains and waterways. Plus, she says, they’re beautiful.
We need more trees and shrubs in our cities and towns, not just to increase canopy cover but to replace those we are losing. And since more than half of most urban land is privately owned, it’s not just up to municipalities to make this happen. Homeowners and anyone else with access to land can – and should – contribute to the expansion and stewardship of the urban forest.
When it comes to planting, trees can be tough, but they’re not invincible. That’s why timing is key. The cooler temperatures of fall and spring are ideal, McKay says. The best windows are when the ground is not frozen but the trees have no leaves.
Getting started: Consider location, location, location
One key consideration is putting the right tree in the right space, says Lorien Nesbitt, an assistant professor of urban forestry and environmental justice at the University of British Columbia. That means the first step is research. Choose a site that won’t conflict with infrastructure such as power lines as the tree grows, she says. If wildfires are a risk where you live, look into fire-smart landscaping recommendations such as keeping plants away from buildings.
LEAF often suggests planting in backyards, as they tend to have fewer conflicts, better protection and more soil volume, says McKay. She recommends staying away from property lines to avoid issues with neighbours. Think about how the tree or shrub will grow and how you might want to use the surrounding space in the future. “Longer-term considerations are really important. … It’s amazing how fast trees can grow.”
The next step: Finding your best options
Choice of site leads to choice of species. How big do you want the tree or shrub to get – and how quickly? What kind of soil, sun exposure and moisture does your site have? “It’s better to plant something that’s going to like the conditions you have,” said McKay. “Trying to change conditions to suit something you like the look of is usually a losing battle.” Where you live is a factor, too, which is why Nesbitt suggests seeking help from local resources such as garden centres, botanical gardens or municipal programs.
Once you have a short list of species that fit your space functionally, you can get into preferences, whether that means prioritizing spring blossoms, fall colour, biodiversity benefits or food. LEAF plants only native species; for the Toronto area, McKay suggests options such as sugar maple, for its “brilliant red-orange colour” in the fall; bur oak, for its large canopy and ability to offer food and habitat to wildlife; or serviceberry, for its “lovely white flowers” and edible fruit. “They’re quite hardy and small-growing and can do well in shade or sun.”
On the West Coast, Nesbitt is a fan of the western redcedar because of its cultural significance to local Indigenous peoples and the fact that it’s under threat. (Keep in mind it needs lots of water.) She also values non-native species in urban forests, especially in places and cases when they are hardier than native species or have significance to local communities. Many flowering cherries, for instance, have come here from elsewhere. “But they’re aesthetically very pleasing,” she said, “and they’re a really important part of the cultural landscape of Vancouver.”
McKay recommends Natural Resources Canada’s My Tree app, available for iOS or Android, to find a species suited to your conditions and climate. In Winnipeg, for example, you could consider alternate-leaf dogwood for dry and shady conditions, while in Halifax, a milder climate means redbud can thrive.
Finally: It’s time to get digging
On planting day, McKay recommends the following: Get ready with your potted tree or shrub as well as a shovel, a tarp and wood chips or other organic mulch. Dig a hole the same depth as the pot but with twice the diameter, transferring the soil and any sod to the tarp. If your soil is heavy clay, you can amend it with 15 to 20 per cent compost.
Carefully remove the sapling from the pot, even if it’s made of peat; if the roots are matted, loosen them to allow outward growth. Place your tree in the centre of the hole and view it from multiple angles, ensuring it’s straight. Then fill the hole back in, being careful not to hit the trunk with your shovel. “I usually use my hands to backfill once I’ve crumbled up the dirt,” McKay said. Gently tamp down each layer, removing large air pockets. Aim for the top of the soil to be even with the root flare, where the roots meet the stem.
If you have leftover sod, you can turn it upside down and use it to outline the edge of your hole, creating a well to help collect water. Then add mulch in a doughnut shape. Avoid the dreaded volcano look, with soil or mulch against the trunk, as the wet bark can kill your tree. Finally, water – not too little, not too much. A slow trickle is ideal. Continue to water roughly weekly (except when the ground is frozen) for the next two to three years, checking first with your finger to ensure the soil isn’t already too wet. Replace mulch as it decays – it mimics the natural decomposition in a forest – and do corrective pruning at the year three or four mark, to avoid problems down the road.
This may all sound like a lot of work, but it’s not much to ask when you consider everything that trees give back to us – not just so-called ecosystem services, but the ability to connect with nature in the heart of our densest urban areas. “There’s something really positive about being able to care for something over time,” Nesbitt said. “The stewardship of urban nature provides opportunities for social connection, community building and social resilience in the face of climate change. And being near trees gives us a sense of who we are as humans.”