How Your Plants Fare in Super-Cold Weather

From on January 30, 2009 in Landscaping

Snow Backyard

Reports of record-breaking low temperatures are becoming common across the U.S. as 2009’s winter unfolds. The discussions among meteorologists as to whether or not this trend has to do with global warming are inconclusive, but regardless of the reasons why, super-cold temperatures are likely to have adverse effects on some plants.

How will your landscape fare after exposure to colder-than-usual temperatures? Here are the findings from experts at universities in states where extreme cold occurs.

Oregon State University Extension Service consumer horticulture agent Jan McNeilan says, “Low fall and winter temperatures will have some adverse effect on several types of landscape plants, but permanent damage to the shrubs is unlikely.

“During cold snaps, broadleaf evergreens such as rhododendrons, camellias, and evergreen azaleas are likely to develop brown, scorched-looking leaves, especially on the windward side. The brown leaves are caused by the plant’s inability during sub-freezing weather to replace moisture dried out of leaves by the wind.

“Conifer evergreens, such as arborvitae and cypress, also will show a browning of the foliage. The brown leaves can’t be revived, although a mid-spring application of fertilizer will stimulate new growth that will conceal brown foliage on the plant.

“Camellias, rhododendrons, and other broadleaf evergreens may have fewer flower blooms next spring if developing buds suffer freeze damage.”

Iowa State University Extension’s Horticulture & Home Pest News featured a story on the effects of record cold. In a nutshell, their prognosis is “the good news is that the cold temperatures shouldn’t have a long-term effect on most plants.”

Purdue University’s Extension Consumer Horticulture Specialist B. Rosie Lerner reports
many of the same findings as her Oregon State counterpart. She says, “Many gardeners are seeing the effects of recent cold snaps and extreme wind conditions. The obvious effects include breakage of plants and tree and shrub limbs. But also related to recent storms is the drying effect of high winds on flowers and foliage. Fortunately, plants should be able to outgrow this type of damage because it’s not practical to try and prevent damage during these short-term bouts of cold and wind.”

For garden lovers, this is all reassuring – the experts point to the likelihood of nature to renew itself come springtime, regardless of the harshness of winter temperatures.