By Jennifer Robinson

Every winter, between 200 and 350 centimetres of snow falls. And with it comes salt.

Quebec spreads about 1.5 million tonnes of salt or sodium chloride on our paved roads in winter to keep them as safe as possible, according to the Quebec environment department. The salt melts snow, seeps into the ground and runs into streams and lakes. We are lucky to live in an area where roads in most of our watershed are not salted in winter. Sand is mostly used on dirt roads in winter, and sodium chloride only sparingly in summer to lower dust levels. Officials and environmentalists are not overly concerned with the impact of salt on water quality in Brome Lake and its feeder streams. There are however waterways in Quebec where salt run-off is a much greater problem.

Salt Damage to Gardens and Trees

But gardeners everywhere, especially for gardens near paved roads, should be concerned. Salt and salt spray and mist from traffic on roads can be very damaging, especially to coniferous trees that keep their needles all year. There are lots of examples of dead or dying young pines on Knowlton Road, Lakeside and elsewhere that appear to have been damaged by salt. Salt is not the only reason plants die; newly planted trees that haven’t been watered properly can also turn brown and die. Also, lots of factors affect how much damage salt can do – rain and snow fall, slope of the land, types of soil.

But salt and salt spray are definite culprits. It corrodes and kills. Salt can damage or weaken trees through their root systems and leaves and make them more vulnerable to disease, infestations or winterkill.

Protecting Your Roadside Plants

What to do if your roadside plants are suffering?

The best defence is to protect the plant from spray and mist by wrapping it, or with snow fencing to keep plowed snow and splatter from passing cars as far away as possible. Heavy snow creates protection, and rain can wash salt away. Just as you would wash your salt-covered car in the spring, it doesn’t hurt to give your roadside trees a shower in the spring.

When planting a new garden, consider the location carefully. Also, it is worth doing research on which plants are most salt-tolerant. Sea buckthorn and most junipers are very salt-tolerant, but blue spruce, firs and roses are not.