November snow isn’t unusual, but it can affect our yards and gardens, especially if it stays around for a while.

Our region enjoyed a long autumn, and the grass was still remarkably green before the recent snowfall, and many trees still had leaves. November snows do change the dynamic of our lawns and landscapes.

The following are effects of autumn snow on lawns, trees, shrubs, flowers and gardens.

  • The recent snow fell on ground that wasn’t yet frozen in most of the region. Snow is a good insulator and can prevent cold from going as deeply into the soil. As of Nov. 16, soil is still not frozen at any of North Dakota’s reporting points, which is considerably later than usual.
  • Late-planted trees, shrubs, perennials and bulbs have enjoyed extended weeks in unfrozen soil.
  • Bitter cold that arrives in autumn when soil is bare is usually more damaging than when snow blankets the ground. Snow has a moderating effect, providing insulation to the soil and giving protection to perennial flowers, strawberries and other plants easily damaged by temperature extremes.
  • Many trees were still shedding leaves as the snow was falling. Unless we get above-average temperatures to melt the snow and allow some yardwork, those late leaves will remain wet and soggy under the snow blanket. Removing the leaves from lawns as soon as the snow melts in spring will be important to prevent the soggy mess from smothering grass.
    Early and-long lasting snowfall can increase mold on lawns. David Samson / The Forum
    Early and-long lasting snowfall can increase mold on lawns. David Samson / The Forum
  • Snow mold on lawns, which becomes visible after the spring snow melt, might be worse this year if snow remains longer than normal on grass that’s still soft, green and lush.
  • Because grass remained green and active longer than usual this fall, some lawn owners might not have lowered the fall mowing height. Mowing shorter before winter can reduce the likelihood of snow mold damage and reduce vole habitat.
  • Voles, also called field or meadow mice, seem less common than in previous years, possibly due to the cyclical nature of their populations, but for any voles present, snow gives them protection. When deep enough, snow allows voles to tunnel along the lawn’s surface beneath the snow, causing visible channels revealed when snow melts in spring.
  • Rose bush leaves are still lush green, which is fairly common in fall, but the lack of earlier cold kept roses growing longer than normal with less chance to “harden off,” or toughen up for the winter.
    Most rose bushes currently still have green leaves despite the snow. David Samson / The Forum
    Most rose bushes currently still have green leaves despite the snow. David Samson / The Forum
  • As snow covers rabbits’ leafy green food sources, they turn to the succulent twigs of shrubs like burning bush, rose, spirea, hydrangea, arborvitae and others. Snow is a reminder to apply protective fencing or repellents like Liquid Fence and Plantskydd to plants favored by rabbits. Rabbit activity is easily monitored after snow has fallen, simply by watching for tracks.
  • Early snowcover that moderates soil temperature can provide a safe haven for disease organisms and insects that spend the winter in the soil. With less winterkill of these pests, disease and insect problems can sometimes be worse the next growing season, if soil temperatures remain mild throughout winter.
  • Grass seeded later than Sept. 15 that germinated and began growing is more likely to survive winter with early snowcover, versus frigid temperatures without snow. Grass that was dormant seeded right before the snowfall benefits from the protective covering.
  • Winter damage to tree, shrub and perennial roots could be less this year, compared to a dry fall. This autumn’s moist ground, plus the recent snow, prevents frost from penetrating as deeply into the ground. Frost can extend farther if soil is dry.
  • Early, wet snow can weigh heavily on the flower clusters of hydrangea shrubs. The dried flowers are decorative in the winter landscape, but if the snow-laden blossoms appear to cause potential branch breakage, the clusters are better snipped off.

Don Kinzler, a lifelong gardener, is the horticulturist with North Dakota State University Extension for Cass County. Readers can reach him at donald.kinzler@ndsu.edu.