Another DIFFERENT Winter!

I've just about decided that I don't know where I live anymore. This looks like my house and my neighborhood, but the winters have seemed to be from other places recently. The winter of '95-'96 was straight out of zone 2! We had actual temperatures below -40 and windchills in the -70s. There was a layer of ice on the bottom of the heap that stayed all winter, making the shoveling and plowing extremely difficult. Last winter, it snowed before the ground was thoroughly frozen. The ground was never uncovered again until mid-April and the snow depth was a near record, so the soil below thawed and remained that way. Our tender babies were protected beautifully until the snow cover went, then they started their joyous spring sprouting and were blasted by four days of single digit temperatures. 1997 became the spring of no tulips!

Today it is snowing and the temperature is about 4 degrees. Just last week it seemed we were in zone 6 instead of zone 4. There was no snow and the temperatures had averaged nearly 20 degrees above seasonal norms. This should have been good news unless you are a Minnesota gardener. One of the most important things for us is a good, consistent snow cover. It is about the best insulation we can get and makes it possible for me to create zone 5 microclimates for those not-quite-hardy plants that I long to grow from my warmer past.

I'm already trying to guess what the two dips into below zero cold without snow cover will mean when spring comes. The extremely warm weather had allowed the Vinca major stumps left in my porch boxes to resprout though they are now residing in the unheated garage. I had heard reports of lilacs budding and tulip and daffodil foliage appearing. What's happening here? Lots of plants seemed to think spring had come. Well, no wonder! The one small encounter with true winter in early December reached -4 degrees for 3 nights straight, then rebounded to lows near or above freezing. Daytime temperatures in the upper 30's and even a few low 40's came next and lasted for several weeks.

Plant hardiness is a very complicated thing. It's not just a matter of how low the temperature in their environment goes, but also when and for how long. To put it in the simplest possible terms: plants adapted to climates where the temperature drops below freezing for some part of the winter go dormant gradually, triggered by the cues of diminishing light levels and falling temperatures. The degree of hardiness of each plant is genetically determined by the conditions where they evolved. By the time the temperature reaches its winter low, the hardiness level is at its maximum for that plant. Garden hybrids may be more tender or tougher than their native cousins due to the introduction of genes from other habitats.

Go To Page: 1 2

Articles in this Topic    Discussions in this Topic