Protect your ornamental plants during the harsh cold conditions this winter. Cold damage can occur on any part of the plant, but we typically notice it first on the leaves and stems. Ice will form within the plant’s cells and plant tissue will die, resulting in brownish-black and mushy plant material. We may not see the affects of the damage until the following spring when the plant fails to leaf out.

Windy conditions along with the cold can cause plant damage by losing more water to evaporation than the plant can absorb. These symptoms may include brown edges and tips on leaves. They may even fall off completely.

The best way to protect your plants is with prevention. There are methods such as plant and site selection that you would consider when installing ornamental plants in your landscape. Fertilizing can strengthen your plant, but should be avoided at this time of year because it could encourage new growth that will be less hardy to the cold. Pruning should be considered only after the threat of cold temperatures has passed. Transplanting should also be avoided during the later fall/early winter time as the plants won’t be acclimated to the cold temperatures.

However, there are measures you can take to protect your plants right now.

  • Place plants that don’t require full sun in the shade as the shaded area will reduce heat loss into the atmosphere.
  • Make use of windbreaks such as fences, buildings, evergreen plantings, and temporary structures to protect from cold air masses moving into the landscape. Use windbreaks where wind is a problem – often the northwest side of a planting.
  • Place container plants inside a protective structure such as a house, garage, greenhouse, or shed or you can place a protective cover directly over the plants. Container plants are more susceptible to cold damage as their roots are exposed. Push these plants together to decrease heat loss, wrap the bases of the containers in plastic, burlap, or blankets to provide insulation when these container plants are left outside.
  • Mulch will help reduce heat loss from the soil.
  • Sheets, blankets, or cardboard boxes can be used to protect plants above ground (avoid plastic here as it can heat rapidly in the day and damage your plants). If you use a cover, remove it during the day to allow the plant access to sunlight and release excess heat.
  • Moist soil absorbs more heat (mulch can also retain moisture close to the soil). Plants still have water needs in the winter, so be sure to check if irrigation is needed before a cold snap
Row Covers | University of Maryland Extension
Image taken from University of Maryland Extension

Information for this article has been taken from the Winter Protection of Ornamental Plants (C872_7) publication by Robert Westerfield and Orville Lindstrom.

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