From the Viette's Views Gardening Blog
The high temperature for Fishersville, VA was only 11°F today. The low tonight is supposed to be four below with a wind chill of -8! Everyone in New England is probably laughing at me – considering this to be a heat wave compared to what they have been experiencing during this very cold winter.
Luckily, we have a bit of snow to insulate our plants during this frigid cold snap. It isn’t as much as we had hoped, but it will help. I know the vineyards in the area were hoping for at least a foot during this last storm. With the extreme cold that is now upon us, they were hoping to have a good snow cover to protect the grape vines. Unfortunately for them, the storm didn’t pan out as predicted. This was a light, fluffy snow that came down in fine, tiny flakes and accumulated very slowly. The totals in most places fell way below the 8″-12″ that was predicted. We only got 4.5″ at our house – but still, it was beautiful and it will provide some protection for the plants in our gardens.
Snow has excellent insulating properties, especially when it is at least 10″ deep. The temperature under a deep snow pack is generally around 32 degrees even when the air temperature is below zero! I suppose this might be some consolation for those New Englanders who are buried under several feet of snow. They certainly have been hammered up there! Of course, with that much snow, many shrubs could be pretty flattened by the spring thaw!
Here are some tips to help with that when the time comes.
Frigid temperatures without any snow cover can be very damaging to some of the trees and shrubs in the landscape. Those that are marginally hardy where you live are especially susceptible to winter damage and winter kill.
I expect that there may be a lot of winter dieback on crape myrtles and butterfly bushes in our area after this winter. Get your pruning shears and pruning saw ready! Hopefully the roots will be protected underground. If the roots survive, new growth should pop up from below to form a new plant.
Luckily, the wind chill does NOT affect plants; only the actual air temperature. Wind chill only affects warm-blooded animals like us and our pets, farm animals, even the wild creatures like birds and mammals; critters that are trying to maintain a constant body temperature.
What can harm the plants are the drying effects of the wind. The air in winter is very dry, as evidenced by our dry skin, chapped lips, and static electricity shocks! When the wind blows this cold, dry air over the plants, it carries precious moisture away from the surface of the plants. Evergreens, both broadleaf and needled, are especially affected because they continually lose water through their leaves during the winter; the wind accelerates moisture loss. When the soil is frozen or dry, it is hard for the plant to replace this water by uptake through the roots. This can result in winter damage and winter burn to leaves and even whole branches.
Rhododendron leaves droop down and curl up tight like little cigars when it is extremely cold. This is a reaction to the cold temperatures but there is still a debate as to why they curl. Read more about it – it’s pretty interesting!
One way to help protect your evergreens from wind burn and winter damage is to spray them with an anti-desiccant like Bonide Wilt Stop. Wilt Stop protects evergreens from winter injury by forming a soft, clear flexible film over the leaves. Wilt Stop also protects evergreens from salt damage which can occur when you have a hedge near a road where salt is spread during the winter. Apply according to the label directions.
There was some discussion after I posted this blog as to whether anti-desiccants can cause problems for plants when the saturated soil thaws and they begin drawing up moisture again. She had heard that the anti-desiccants may prevent evapotranspiration and plants can suffer as water they absorb is trapped in them.
I contacted Bonide about her concern and their response was, "Wilt Stop will not cause problems in the spring with evapotranspiration. It just slows it down. You are correct, it can be sprayed during the spring, summer & fall using the "summer" mixing rate, which is a lighter mixture than what is used for winter protection. One just needs to follow the label instructions."