With all the vagaries of our weather in recent years, my winter forecast is that it will be either warmer than normal or lots colder, leaning toward the latter. In either case, it would be wise to survey your landscape to see where some protection might be a good investment.
The wisest approach is to select hardy Zone 5 plants for your landscape, then place them in a site that will take advantage of the terrain—or perhaps consider buildings for additional protection. South-facing slopes are great because of sun all year long, with cold air drifting downhill. In front of a stone wall is also an option because the wall retains heat.
Cold damage takes different forms and affects foliage, buds, limbs, and trunks in different ways. Often it’s not the lowest temperature that does the damage, but instead, the duration and timing of cold weather.
The 2007 Easter Freeze came after a prolonged warm spell, long enough to convince some plant species, like Japanese Maples, that spring had already arrived. Even short variations in temperatures can cause buds to break dormancy and lose their hardiness.
For the roots, a good layer of mulch is the appropriate defense. Mulch doesn’t keep the soil warmer but it does slow the freeze-thaw cycles. Once the soil gets cold it stays cold.
You can protect the upper part of a tender plant by surroundings it with a blanket. To do this, drive stakes into the ground around the plant and staple burlap to the stakes as a curtain. Gently stuff the spaces between the branches and the burlap with straw. The intent is to keep the plant cool on warm days, not warm on cool days, which is why burlap is better than plastic. Burlap breathes, keeping the temperature more in line with the ambient, eliminating sudden, short periods of heat. Plastic, whether black or clear, traps the air and allows it to swing above ambient for short periods of time.
The same concept can be used to protect evergreen plants against sun or wind burn. Waxy chemical sprays on the leaves can also help prevent desiccation from the wind. This is particularly appropriate for Rhododendrons in windy locations.
To help prevent snow or ice from bending long, pliant branches on a tree or shrub, one can wrap the plant with tape or twine, like a Christmas tree.
Written by Glenn Palmer, originally published in the Asheville Citizen Times.