If you’re an avid gardener, you’ll know that a good layer of snow serves as an excellent source of insulation for your plants.
Deep snow, which I would classify us as currently having, can maintain soil temps high enough to sustain microbial activities and mineralization processes through-out the winter.
It seems as though our beloved plants do a better job of getting ready for the brutal temps of winter than most of us humans do. Plants get ready for winter by undergoing a process called acclimation or hardening. Hardening is triggered by various environmental cues like the day length, cooling temperatures in the fall and in some cases moisture availability. Unless we’ve experienced arctic temps in the early stages of acclimation, which I don’t think we did, you can be confident that your plants have done their part in preparing for the type of winter we are experiencing right now.
But John, what about the arctic wind chills we have been experiencing? Since plants do not generate their own heat, wind chill does not affect them (I really wish I was a plant right now). But cold and dry winter winds can damage plants by drying them out. This is particularly a problem for evergreens that have leaves exposed to the wind during the winter.
Plants are generally able to withstand these colder temperatures by regulating the water content inside and around the plant’s cells. The water around the plant’s cells is usually the first water to freeze because the water inside the plant’s cells has various salts and other compounds dissolved in the liquid component of the cells. But, once the water around the cells freezes and forms ice crystals it can damage surrounding cells and draw out some of the water inside the cells which can lead to larger ice crystal formation and damage to the cells themselves. The various processes that plants use to withstand sub-freezing temperatures are quite complex and can vary dramatically from one species of plant to another.
In summary, all scientific data that I have read indicates that majority of our plants will pull through this brutal winter. Of course this means if they are cold hardy (Zone 4 or lower). I say 4 or lower because it seems debatable whether our region is Zone 5 or not. Don’t be too surprised if you lose a couple plants that are zone 5, but then again I’m sure you’ve lost some zone 5 plants in much milder winters as well. On a side note, let this winter be a reminder of why overwintering plants properly is crucial. Read more about the process of over-wintering as well as other 'need-to-know' plant care info at: http://bluemels.com/caring-for-perennials/4580854136
Personally, I think how this snow melts come springtime will have more of an effect on the survival of our plants than this winter will. A gradual melting would be ideal. If it all melts at once, similar to how it did a couple of years ago, plant roots will rot out In essence they’ll drown to death.
So sit back, relax and enjoy the cozy warmth of your home. Dream of the upcoming spring that is right around the corner. At this point, I think your plants will be alright and there isn’t a whole lot of need to worry.