After all of the excitement of the December holidays and as we hunker down with dogged determination to overcome winter, let’s shed some warmth on why snow is so good.
Winter is marked by low temperatures (oh yes, don’t we know it!) and low levels of ambient sunlight. Think of snow as a winter insulating blanket and a moisture insurance policy for spring. Snow has varying degrees of insulating power to moderate the overall ground temperature. Usually fluffy fresh snow has the greatest insulating capacity because it possesses the most air spaces. Air is what gives snow its insulating clout, up to six times greater than soil compared to an equivalent depth. Pomeroy & Brun, who wrote “Physical Properties of Snow” cite that 10 inches of freshly fallen snow is equivalent to a 6 inch blanket of insulation, approximately a value rating of R18. Heavy wet snow, therefore, is less effective at protecting from cold because of its decreased amount of air pockets. Also as a blanket, snow protects the crown of plants from wind and protects perennials from the freeze / thaw cycle of spring by stabilizing the ground temperatures and keeping the crown protected.
On a practical note for the home garden, spots to watch for adequate snow cover is under eaves, in narrow passages between buildings, and where furnace exhausts and drier vents blow. These areas often have a decreased amount of snow due to roof interference from snowfall, wind blowing snow from narrow spaces, and melt from the warm air exhausts. When shovelling sidewalks, be sure to throw the snow in these areas to build up the snow cover.
Some perennials with nice winter garden interest include ornamental grasses, tall fall blooming sedums, german statice, limonium, and gas plant. As you plan your garden for 2016, consider including some of these in your landscape. In the meantime, let’s hope for a little more snow.