Gardening Tips: January 2, 2013
Coping with Winter
Now that we finally have had to deal with some “normal” wintry weather it is time to reflect on how other creatures cope with less than comfortable conditions. Many species of birds as well as many humans simply head south to spend the cold months in a familiar, warm location. Birds must look forward to the annual migration as much as some of us humans do once ponds and other sources of water freeze and food supplies diminish or disappear under blankets of snow and ice. Insect, seed and bud feeding birds may change their diets somewhat and some mammals like bears and woodchucks simply sleep it off while others like weasels, shrews, foxes and mink step up their hunting efforts.
I find myself spending more and more time in Florida for several reasons. First, of course, is because my kids and grandkids live near Tampa and I get to see them on a regular basis when I am staying nearby. Second is that 70 degrees seems to suit my body and my mood very well compared to 30 or less, which is the norm for our region. It is true that I can ice fish once the ponds are frozen but I prefer to fish without dressing like an Eskimo.
Plants, being rooted in one place, do not have the luxuries that animals do and they have evolved some very interesting survival tactics to cope. Many fleshy, perennial plants allow their above ground foliage to freeze and disappear while their roots are somewhat insulated by the mass of soil that surrounds them.
Trouble with the thaw
Most perennials can deal with frozen soil all winter long but sometimes perish when the ground beneath them thaws and re-freezes over and over. This phenomenon is known as “frost heaving” and explains why some plants seem to rise to the surface each winter as though something dug them up. The water in the soil beneath them freezes and pushes them upward the same way it forces rocks and stones to the surface every spring. This is why your gardens grow a new set of rocks every year despite your diligence in removing them all summer long.
Deciduous trees and shrubs drop their leaves and rely on bark to insulate the tender tissue beneath it. Bark is a good insulator but the tree or shrub must often expend energy to prevent water in their interior plumbing from freezing solid. Evergreen trees are actually hardier than deciduous trees; which is surprising, considering that they retain green needles all winter long. Green needles will try to photosynthesize on warm, sunny, winter days. This is impossible when the roots are in frozen soil but the plants that really have it the toughest are the broad- leafed evergreens such as rhododendrons. These shrubs will curl up their leaves into cigar-like tubes to reduce the green tissue visible to sunlight on very cold days.
Right now would be a good time to apply an antidessicant to the undersides of rhododendron or even holly leaves. Antidessicants , such as “Wilt Pruf” function by clogging the tiny pores on the underside of the leaves (stomates). This prevents water loss and desiccation of the tender leaves for about six weeks. The next time to apply the spray would be around mid February.