Preparing Plants for Winter

The effects of winter damage are often slow to appear. Plants may seem to have come through tough weather, but as spring approaches the edges of leaves turn brown and bark may split, leading to the death of a branch or even the death of the whole plant. The cause of this type of damage is temperature fluctuation. If the temperatures stay cold, plants go dormant. During this dormant period plants do not take in moisture or transpire (transpiration is the act of moisture leaving plants through its leaves). However, in our area we often have cold snaps followed by warm, sunny days. With these warm days, leaves may begin to transpire, but roots, still in frozen ground, are unable to replace life-sustaining moisture. Under these conditions, plants easily become dehydrated.

The types of plants that are most likely to suffer from winter damage include broadleaf evergreens (evergreens with leaves instead of needles such as hollies, rhododendrons and laurels), Leyland cypress and Serbian spruce.

There are easy steps to take to prevent or minimize this problem.

  • Make sure plants are healthy going into winter. Keep plants well watered, especially during dry summers and autumns.
  • Spray Wilt-Pruf on the foliage of broadleaf evergreens. This will provide a barrier, keeping moisture from transpiring. You must spray both sides of leaves and the solution must be applied on a warm day so the Wilt-Pruf can dry correctly.
  • If plants are exposed to winter winds, create a windbreak. One of the easiest and best windbreaks is constructed of burlap stapled to wooden stakes driven into the ground. This windscreen will provide protection while letting plants breath.
  • Gently brush snow from the branches of boxwood, arborvitae, Japanese maples because these plants' branches may break under the weight.
  • Do not attempt to remove ice from any plant. You will do more harm than good.

If damage does appear

  • Dehydration can take many months to correct. If dehydration occurs, be sure to water the plants throughout the spring and summer.
  • Most damaged broadleaf evergreen leaves will fall off on their own. Resist the temptation to prune. While the leaves may die, the branch is generally alive and the plant is able to produce new foliage.
  • Don't assume that deciduous plants (those that lose their leaves in the winter) are dead if they fail to leaf out normally in the spring. Flowering plants may not bloom if temperatures were severe. Their buds may have frozen. Do not give up on your plants until June.
  • Prune cracked branches immediately. If these branches are left to hang they can tear further, harming and even killing the plant.

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