Snow in the Garden
Last week, we had unseasonably warm temperatures and heavy rain here in Maine. One night, I checked the deck thermometer at 3:00 a.m. to find that it read 45F; this is 40-50 degrees higher than our typical overnight lows in January! Throughout this “January thaw,” I kept an anxious eye on the snow pack in my garden. While gardeners in more temperate climates may worry about how a freak snowstorm will harm their plants, cold climate gardeners worry about how the absence of snow might harm theirs.
I’m not denying that snow and (especially) ice can create problems in the garden. During the great ice storm of January 1998, when Maine and Quebec experienced several days of freezing rain followed by frigid temperatures, tree damage was enormous. During the long, dark (powerless) nights, the booming sound of cracking, breaking and splitting trees was like cannon fire. Almost all trees lost limbs, and many large, venerable old trees simply split apart under the weight of all that ice. Even a more ordinary winter event, heavy snow and ice avalanching off roofs, can do serious damage to shrubs planted below.
But in this part of the world, snow is primarily a beneficent presence in the garden. Here, as in other snowy regions, farmers sometimes refer to snow as “white manure,” presumably because it locks up moisture during the dormant season and then releases it into the soil in spring to nurture new growth. Even more importantly, snow is a great insulator. For perennials that have died back to the ground in fall and whose roots stay alive beneath the ground to produce new growth in spring, the insulating qualities of snow are a boon. An insulating blanket of snow helps to maintain a steady temperature and prevent the frost/thaw cycles that can heave plants out of the ground. And the steady temperature that snow helps to maintain is considerably warmer than the coldest ambient air temperatures. Thus a plant that is rated hardy to –15F or –20F can easily survive nights of –25F or lower if it is under several feet of snow.
I have learned that years of heavy snow will be good years in the spring and summer garden. Two years ago, when we had snow early and often and the snow pack in my garden at the beginning of March was almost 5’ deep, I found parsley (not normally a plant that winters over here) alive and happily putting up new growth when the snow melted in April. It is in winters with little snow, especially if they also have extremely cold temperatures, that I can expect to mourn my garden losses in spring.
When our brief thaw ended last week, I was happy to see that, although there was some bare ground showing around trees and along the foundation of the house, most my garden was still covered by at least 6 inches of snow. As so often happens in late January, the balmy temperatures of the thaw were followed immediately by strong winds and biting cold. Even a relatively thin blanket of snow can help to protect my plants from these temperature extremes. I’m hoping that the rest of the winter will bring more beneficial snow, with its promise of a beautiful, bountiful spring, to my garden.