Bibby and Harold Alfond Children's Garden under a blanket of snow.

Bibby and Harold Alfond Children’s Garden under a blanket of snow.

Are we having fun yet? This season is shaping up to be a “good old-fashioned Maine winter.” We’ve been spoiled the past several years with relatively mild conditions. I was born and raised in Aroostook County; so I’ve felt like the stereotypical old-timer with my “back when I was a boy” stories about “real Maine winters”. (You know the ones: 25 below zero, three feet of snow, and walked four miles to school-uphill–both ways.)

Here at Coastal Maine Botanical Gardens our weather extremes are usually moderated by our maritime location. This enables us to grow more species of plants than our neighbors just a few miles inland. We are classified as Hardiness Zone 6a, a rarity in the state of Maine. Unfortunately, Mother Nature doesn’t read maps all that well. This is when snow becomes a good thing.

Several inches of snow provides a good thermal “blanket” for the roots and crowns of our plants. The air temperature can drop well below zero, but with adequate snow cover, soil temperatures in the plants’ root zones will remain just below freezing. While most of our plants are capable of surviving bitter cold without snow cover, some will not and some will sustain damage that will make them more susceptible to insect and disease problems the following spring.

Snow cover also prevents problems later in the winter. As the sun gradually gets higher, snow reflects the light and warmth away from the plants. Bare ground, on the other hand, absorbs the heat and thaws the ground around the plants. This becomes a problem when night time temperatures are still dropping into the teens and twenties. Damage to the plant crowns, the near-surface roots and possible mortality can occur if this freeze-thaw cycle goes on for an extended period of time.

The plowing, shoveling, and cleaning up after snow storms gets old as the season progresses. Just remember, the next time the weather forecast calls for a foot of snow, at least your gardens will be happy.

- Will Bridges, Horticulturist (January 7, 2014)