Illinoisans often welcome the first few snows of the year with delight, and appreciate a snow on Christmas to set the mood. But continual snowfall gets tiresome to many.
For gardeners, though, snow is necessary for overwintering plants. A layer of snow provides insulation, sun protection, and moisture for dormant plants. When the air temperatures get well below freezing, the snow helps keep the ground close to 32 degrees. The snow also prevents the soil from warming up too fast, which can cause plants to wake up too early. In spring, moisture from melting snow soaks into the soil to plants' roots just in time for them to resume growth.
The salt that is used to melt ice and snow on the roads can negatively impact plants. As salt dissolves into water and spreads to nearby soil, plants take it up. The most common salt we are familiar with is comprised of sodium and chloride. Many other common ice-melter products are made of different natural or synthetic materials. But natural or synthetic, in high concentration, all of these products are toxic to plants, so caution should always be used. Plants vary in their sensitivity to salt, with some plants seemingly unaffected by salt, while others can be killed. Japanese maples, serviceberries, red bud and dogwood are sensitive to salt damage. Juniper, Kentucky coffee tree and Virginia creeper are more tolerant.
Specifically, salts interfere with plants’ ability to uptake moisture and nutrients, and with photosynthesis. Telltale clues are changes to the leaves, needles or flower buds facing the site of salt application. Severe damage presents itself as “witch’s broom,” a deformity at the tips of branches presenting itself as a dense mass of shoots. To avoid salt damage, use sand to add grit when possible, avoid mounding snow around sensitive plants, or erect snow barriers where snow will be pushed.
Another issued associated with winter weather is heavy snow load or ice on your favorite tree. Avoid shaking the limbs as this may damage the limbs. The branches are more flexible and able to hold more snow than you think. If you must remove snow, gently push up on branches from below to prevent adding stress. Allow ice to melt on its own. If small branches are broken, they can be pruned without altering the tree's look. However, any branches that would require a ladder to reach, or large branches that are broken, may be best left to a professional or your municipality if the tree is between the street and the sidewalk.