Along with aesthetic and safety issues, many enlightened municipalities now take invasiveness into consideration when choosing street trees.
Invasive varieties to avoid include Norway maple, black locust, Siberian elm, Russian olive, and European and common buckthorn.
In this era of heightened awareness and anxiety over climate change, the increased focus on the environmental importance of street trees—and the urban forest in general—is a positive development. But Kenney warns that we’re neglecting the other half of the equation: “We plunk trees in the ground, walk away and hope for the best. We plant a lot, but that’s only part of the story. How many survive?” It’s in the care—the watering and mulching, for example—that municipalities and residents need to start working on together. Perhaps, then, our urban street trees—which currently have an average lifespan of just seven years—will reach the grand old age they deserve.
Caring for your boulevard tree
The boulevard tree is in the ground, the municipal planting crew is gone—now the important work begins. The first three years are critical to the survival and long-term health of any specimen, and each of us has a role to play. Watering young trees, especially during periods of drought, is the single-most useful thing that residents (homeowners and renters alike) can do for the trees planted on city property in front of their homes and apartments.
- For its first three growing seasons, soak the tree for a half-hour at least once a week, preferably in the early morning; don’t water if there’s been plenty of rain, as tree roots can die from excess moisture.
- Conserve moisture, suppress weeds and supply nutrients by creating a saucer of mulch around the tree, one to two metres away from its base (i.e., the mulch should not touch the bark). Mound the rim around the saucer to hold in water.
- Keep the mulch weed- and grass-free. Do this by hand, not with machines, which can damage bark.
- In winter, avoid using de-icing salt, which can harm trees; apply sand instead.
Your tree is in the ground; now what? Check out our tips on how to beautify your boulevard!