Thursday, November 20, 2014
By Stephanie Hughes
OSU Extension master gardener volunteer
Our Plant & Pest Diagnostic Clinic at the OSU Extension office in Canfield was busy from spring until fall with samples that were still linked to last year’s winter conditions. The most lasting effects of the winter are evident in evergreens, with arborvitae being the most problematic plant. We had more arborvitae samples this fall than just about anything else. Many of the fungal pathogens we are finding in arborvitae are there due to the stress and injury from last year’s winter.
Winter injury may manifest as excessive browning of evergreens, injury (death of buds), splitting of bark, and death of roots. Most of the browning is desiccation. Desiccation is water loss that occurs faster than moisture can be replaced due to freezing temperatures (no root absorption). This water loss occurs for several reasons, but mostly due to air temperatures, humidity levels and wind.
The effects of winter weather can be reduced. Even if this winter is not as bad as last year, many gardeners may choose some methods of winter protection just in case.
Mulching is one of the easiest things homeowners can do to protect plants. Gardeners should use 2-2 Ω inches of mulch applied to soil after soil freezes will keep soil cold. This reduces injury from heaving (brought about by the freeze/thaw process). Mulch maintains soil at a constant temperature, helping to maintain moisture.
Another practice to help cut down on heaving with heavy clay soil is to mix it with 1/3 to Ω organic matter, such as compost or peat moss to keep soil frozen and thus preventing the freeze/thaw process which heaves up plants, which leads to winterkill. This practice should be done when planting new flower beds or trees.
Using fencing to block prevailing winds or wrapping plants with burlap, with leaves packed loosely inside will help plants overwinter better. A break wall of burlap stretched across the yard where prevailing winds blow will also be of help.
Tying is another option. Taller evergreens with multiple leaders, such as arborvitae or junipers, can be damaged by the weight of snow and ice. One of our experts, Mary Ann Rose, suggests to “prevent plant breakage by fastening heavy twine at the base of the plant and winding it spirally around and upward to the top and back down in a reverse spiral.”
Whatever your choice, make plans now to protect evergreens so they will still be a beautiful part of your garden next year.
For more options on overwintering plants in the landscape, go to: http://go.osu.edu/overwinter