Protect Shrubs and Perennials from Frost

Need some strategies to protect your shrubs and perennials from Jack Frost? If you live in a snowy winter area, planting cold hardy plant species are your first line of defense against dead plants. Cold hardy or not, they can always use the gardener’s help to take them safely through the winter.

Predict a Frosty Night

Many areas that see little or no snow, yet experience light, hard frosts, and freezes. In this case, general frost protection can make all the difference. Mother Nature sends clear signs that temperatures are about to take a dive.

  1. Clear skies without a cloud in sight.
  2. Night air that’s dry and still.  Still nights mean cold air will settle on the ground, while a light breeze stirs the air up and reduces the chance of frost.
  3. Cold air settles in valleys and hollows first. Keep an eye on a yard or garden that’s situated in a valley.
  4. The lower the forecasted dew point, the greater chance that frost is on the way.

Frost Protection Strategies

Most cold-weather protection will involve using some type of barrier placed over the plant. However, there are other techniques that will help prevent frost or snow from damaging plant foliage.

  • The first thing is simply to drag any potted plants underneath a porch cover.  Utilize the techniques below if they need additional protection.
  • Before winter (around early fall), mulch perennials with 4”- 6” inches of straw, dried leaves, or shredded bark around the root base. Be careful not to pile the mulch up onto trunks or stems of the plant.  
  • Water traps heat, therefore, roots will stay warmer when there is water present in the soil. If you live in an area that has little or sporadic rain, your plants will need to be irrigated through the cold months. Water them deeply in the morning several times a month.  
  • Tender bulbs such as dahlia, ranunculus, caladium, canna, begonia, freesia, and gladiola should be gently lifted from the soil in the fall and stored for the winter. This way they can be replanted next season. Bulbs such as daffodil, tulip, hyacinth, and crocus are hardy and will tolerate hard freezes.
  • Young trees (or delicate ones like citrus) benefit from burlap wrapped around their trunks.
  • Cardboard boxes placed over shrubs at night make good frost barriers for both in-ground plants and potted shrubs.
  • Cloth tarps, burlap, recycled sheets, and blankets can be used as frost barriers over plants. Ideally, the covers should be used in combination with a wood frame, bamboo stakes, etc. to keep the fabric from touching the plant’s foliage.
  • If possible, use material long enough to drop all the way down to the ground, to take advantage of the heat radiating from the soil.
  • Create removable ‘boxes’ using thick plastic stapled to a wooden frame. It is effective, but the box should be removed from the shrub during the day (warmer temperatures) and then replaced at night.  
  • Purchase special frost protection bags or fabric rolls from your local nursery. It’s made to wrap directly around shrubs and trees without any worries about it touching the foliage.

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