University of Vermont Extension 
Department of Plant and Soil Science

Winter News Article


Charlie Nardozzi, Horticulturist
National Gardening Association, and
Dr. Leonard Perry, Extension Professor
University of Vermont

Keeping ice off roads and walks, safely, checking houseplants for spider mites, and picking the best poinsettias, are some of the gardening tips for this month.

Although salt does melt ice, it also can damage plant roots, so substitute sand or kitty litter to provide traction, or use one of the commercially available products made to melt ice without damaging plants.  Some combine some deicing salt with sand or kitty litter.

Watch for new agricultural-based deicing products.  These are relatively new, and include byproducts of grain, corn, and beet processing.  As you might expect, they are much safer for the environment.  Often these may be combined with magnesium or calcium chloride, each safer to plants than the common sodium chloride.

When the ground freezes, it's time to mulch tender perennials, newly planted trees and shrubs, roses, and other plants that need protection. Use straw, hay, compost, evergreen boughs, leaves (except for maple which easily compact), bark chips, or whatever else may be available locally that doesn't mat down too much. Certain drought-tolerant perennials, such as agastache and penstemons, are better off with a gravel mulch, which won't hold water. If burrowing rodents are a potential problem, leave a 2-inch gap between the mulch and tree trunks so the critters can't feed under cover all winter.

If your birdbath is within an extension cord's reach of your grounded outdoor outlet, you can provide drinking water for winter birds by using a birdbath heater. It keeps the water slightly above freezing. Just be sure you don't run over the cord with your snowblower.

Snowfalls can be tough on trees and shrubs by weighing down the branches, as many in northern areas found this past year with an early, heavy snow. Gently brush off most of the snow with a broom or by hand. Don't use a shovel, which can injure the branches. If there is ice buildup, it's best to let it melt because it's easy to break off the brittle branches if you try to remove it.

If Mother Nature hasn't blessed you with several inches of snow cover on your lawn, don't walk on the frozen grass. Without the protection of snow, grass blades are easily broken, causing dieback in your lawn that will show up next spring. Put up flagging or stakes in sensitive areas to keep visitors on the path.

Many houseplants, including palms and cyclamen, are attacked by spider mites this time of year. They are microscopic creatures that suck plant juices, causing the leaves to look speckled or silvery. To scout for these pests, mist the plants lightly; if mites are present, the water droplets will cling to the mites' fine webbing. Control them by misting plants daily to keep the humidity high (spider mites love dryness) and by spraying plants with insecticidal soap.

When choosing your poinsettias this holiday season, make sure to pick the best that will last the longest.  Check the little yellow flowers in the middle of the red or colored bracts (these are actually leaves that changed color).  These tiny, inconspicuous flowers should be present, and unopened.  Otherwise plants may be old, or watered improperly.

Keep poinsettias protected from cold—both on the way home from the store, and at home.  Keep them away from cold drafts near doors and windows.  Wilting leaves may be a sign of cold injury, or too much water.  Poinsettias prefer more dry than too wet.

Other ideas for this month include shopping at your local garden store for holiday gardening gifts, checking holiday indoor trees daily for water needs to keep them long-lasting and safe, and making holiday decorations from natural materials.  Visit the National Gardening Association’s web site ( for more information on gardening and regional reports.

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