As unusually early frigid temperatures set in across the nation, many Americans are not thinking about their landscapes as much as they are worried about staying warm. However, plant material is just as shocked as animals when the weather quickly turns from sunny and mid-60’s to snowy and single digits in less than 24 hours. This is a meaningful short term shift, and there are a few tasks that property owners can do to save their vegetation from detrimental shock.
Even though the ambient temperature is well below freezing, plants do not immediately stop transpiring. Extreme cold can make both atmospheric and soil moisture less available to plant material, so it is important to make sure that tender plants that haven’t completely hardened off are receiving adequate moisture. To prevent water freezing to the foliage and basically suffocating the plants, it is important to water the soil directly, making sure that excess water does not freeze to the leaves and stems. The water that is applied should be cold, as hot water can both shock the roots and also freeze quicker. Also, if it hasn’t been done already, a late fall application of fertilizer will help fortify plant material during the winter, as the plants never stop living. When a plant has yet to harden off, though, there are a few practices that should be avoided.
When a plant still has foliage on it, if snow or frost accumulates on the leaves, a natural tendency is to knock the precipitation off. This should be avoided at all costs. Unless there is an unusually heavy snow that is literally shredding the plant material, precipitation on leaves should be left alone. When the branches are shaken or foliage damaged, the plant becomes open to insects, diseases, and other stressors. It is important to leave the precipitation frozen to the leaves to naturally melt off, when there is no threat to the structure.
Another practice that should be avoided is covering plant material with foreign materials. Plants should never be covered in plastic, bed sheets, or any other wise-tale method of preservation. Covering plant material with any foreign material will harbor insects, disease, and create rapidly changing micro-climates as the sun and clouds continuously raise and lower the temperature under these materials. Frankly, if it’s November, the tomato plants are ready to get cut down anyway. Seasonally durable materials like woody trees and shrubs will do just fine throughout these temperature changes and covering them with foreign materials will only do more harm than good.
When it comes to freezing cold and winter precipitation, there are a couple practices to conduct and a couple to avoid that will drastically help landscape plants live through the winter. With adequate water and food is combined with minimal mechanical damage, plant materials truly have the best chance of surviving through the rapidly changing conditions that are currently sweeping across the United States.