Newly-planted evergreens are more prone to being dehydrated through the winter, said a University of Illinois Extension horticulture educator.
"Winter can be harsh," said James Schuster. "Long, cold periods with drying winds can help dehydrate the new plants. Since evergreens, both needle and broadleaf, maintain live foliage through the winter, the foliage continues to loose moisture even when frozen. If the water loss is too great, the needles or leaves will turn brown as they dehydrate and die."
Several cultural practices may prevent this outcome.
"First, make sure there is plenty of soil moisture before the ground freezes," he noted. "Water the planting hole as well as a couple of feet of the surrounding soil. Avoid over-watering. Over-watering can drown tree roots, adding to winter kill."
Application of an anti-desiccant/anti-transpirant should be considered. Schuster said it is important to read the product's label and use the winter label rate at the recommended temperature.
"These products vary in their longevity and effectiveness on the plants," he said. "Usually a second and sometimes a third application later in the winter are required. When applied correctly, these products can sometimes make the difference on plant survival, as well as appearance the following spring."
Another way to reduce dehydration is to make a screen to partially block the wind. Use sturdy stakes that are a couple of feet longer than the plant is high. Place the stakes in the ground before the ground begins to freeze.
"How many stakes depends on whether you want a 'v-shaped' screen or a flat screen as well as how many evergreens were planted," Schuster noted. "Once the ground begins to freeze, nail, staple, or tie a material like burlap, a cheese-cloth-like material made out of nylon or other polyester, or even snow fencing to the stakes.
"If using the 'v-shaped' screen around an individual plant, the bottom of the 'v' stake should be directly west of the plant. The other two stakes are to the southeast and to the northeast of the plant. The entire east side of the plant should be left open."
Schuster said the plant should not be wrapped entirely with protective material.
"This barrier is to reduce the flow of wind through and around the evergreen," he said. "It is not supposed to stop the wind entirely.
"Make sure light reaches all of the plant so do not situate the screen so that it touches the plant."
Source: James Schuster, Extension Educator, Horticulture, schuster@uiuc.edu
