The snow-covered landscape and bitterly cold temperatures are leaving gardeners and homeowners wondering, "Are my plants faring better than me this winter?"
Personally, this gardener has been fighting multiple colds, dry sinuses, dry skin and bone-chilling walks from my car to work. From my perspective, the plants are adapting to this winter season better than I am, because they have adaptations to things like snow cover and chilling temperatures. However, plants can be susceptible to winter wind and sun.
In the fall, when temperatures cool and the days become shorter, the plant starts to harden off by regulating the water content inside and outside of the cells. Frozen water in plants will destroy the cells. The level of hardiness a plant reaches is genetically predisposed and builds up over the winter season. This is why you will never see palm trees lining the streets of downtown Bloomington; they simply are not hardy enough for our environment.
Snow cover can actually be a blessing for plants by providing a layer of insulation and protection from the winter winds and sun. Snow usually remains at temperatures in the 20s and 30s and may keep plants at higher temperatures than if they were exposed to the air.
My father worked for a botanical garden in New Orleans and was responsible for a small orchard of trees. One night the temperatures were getting dangerously low so he put on the water sprinklers. The buds were then encased in ice and kept at around 32 degrees, which was much higher than the actual air temperature saving the buds in the orchard. This year in Central Illinois, we may have issues with peach tree buds not holding up through the extremely low temperatures.
The drying winter winds that chap my lips can also dry out our evergreens, stripping them of all the moisture they contain. This is why it is important to never let evergreens go into the winter dry and to put down mulch in the fall. Mulch helps regulate temperatures and conserves moisture. On a good note, plants do not experience wind chills like we do. The wind pushes heat away from our bodies, but plants do not generate heat the way we do and derive their heat from the sun.
The sun can be an offender this winter. If you have a young maple, you may experience a frost crack on the south side of the tree. This is where the sun has heated up the cells to the point they become active, only to cause severe damage when lower night temperatures return.
You also may see this effect with evergreens like arborvitae and yews where the south side of the foliage shows winter burn in the spring.