The woolybear caterpillar indicates the coming winter will be a rough one. The new edition of Gruber's Hagerstown Almanac says it probably will be worse than that of last year.
Many kinds of garden plants may be damaged by severe winter weather. Sone of the damage is not serious enough to worry about, some can be prevented, and some is beyond one's ability to do anything about.
Extreme cold is one of the worst problems of many kinds of evergreens. If the ground stays frozen to a greater depth for a longer period of time, the roots of plants are not able to absorb moisture to replace that lost by the foliage.
A two-to-four-inch mulch of ground tree bark, wood chips, sawdust, straw or some similar material will keep the soil from freezing as deeply, also reduce rapid freezing and thawing of the soil and prevent soil erosion.
Oak, sycamore and beech leaves are excellent for mulching if you can keep them from blowing away. They do not mat down and become soggy when it rains. Maple, elm, ash, birch and poplar leaves are undesirable because they do mat when they get wet.
The mulch eliminates the impact of raindrops falling on bare soil. Heavy rain can really batter unprotected soil. The mulch delivers the water gently to the soil surface, preserving its pore structure.
The roots of plants cannot survive the same degree of cold as the tops. For example, the stems and leaves of pyracantha can survive -15 degrees F. when fully acclimated (adjusted to winter weather) but mature woody roots are killed at +2 and young roots cannot survive +22.
When planted in the ground and mulched the hardiness of the root system isn't a problem because the soil temperatures usually do not get low enough to cause damage.
But when growing outdoors in tubs, barrels and other containers, trees and shrubs may be badly damaged or killed unless given some winter protection. The temperature of the soil in the container will be the same as the air temperature and it may go below survival levels.
Once the water in the container soil is frozen, conditions are the same as if the soil were dry. Obviously, ice cannot be taken up by the roots. Watering the containers beforehand does not help this situation much because the extra water will freeze also. This can lead to serious desiccation injury.
About the only way to save them is to move the containers with the plants into the garage or an unheated shed where temperatures will not go much below freezing.
Plants growing in containers that are root-bound particularly should get such protection.
Newly planted evergreens, although normally hardy, may be vulnerable because they have not had time to develop a good root system in the new location. They can be helped considerably by using burlap to shelter them from wind and sun the first winter. Mulching is also important.
The roots of plants in raised beds are likely to experience colder temperatures at the margins of the bed than are the roots in the middle of the bed. To help prevent winter damage, build the beds at least six feet wide and mulch them thoroughly in the fall. If it is possible to build raised beds that slope down to the soil surface, plant the slope with grass. such beds get better winter protection than do beds surrounded by brick or similar materials. b
There has been a lot of research on the value of anti-transpirants or anti-desiccants for prevention of winter injury. They reduce loss of moisture from the foliage.
"I have come to the conclusion that anti-transpirants are not worth beans in reducing winter injury to ornamentals," says Dr. Francis R. Gouin, University of Maryland ornamental horticulturist. But he says anti-transpirants are "a definite asset in summer transplanting of trees and shrubs."