Polar Vortex

By Jeff Rugg

January 30, 2019 4 min read

"If the thermometer was in inch longer we would have all frozen to death." This may or may not have been said by Mark Twain. In "Following the Equator," he did write, "The captain had been telling how, in one of his Arctic voyages, it was so cold that the mate's shadow froze fast to the deck and had to be ripped loose by main strength. And even then he got only about two-thirds of it back."

Twain died many years ago, but he could very well have been talking about the weather we are having this week across much of North America. We have had this kind of weather many times before and will have it many times in the future.

He may have never heard of a polar vortex, but one exists year-round at each pole on Earth and many other planets. When the Artic polar vortex is strong, it stays constrained close to the North Pole. When it weakens, it forms lobes that slide down the face of the Earth, pushing cold weather to the south. The polar vortex this week is similar to one that we had in January 2014. During that one, I made funny videos for my grandkids, such as using a frozen banana to hammer nails into a board.

So, what can we expect in our gardens from such a cold spell? Be thankful if your landscape is covered in snow. Much of the northern U.S. had several inches of snow this past weekend. Snow is an excellent insulator, and it protects a lot of plants. Lawns, ground covers, bulbs and perennials under snow will have little problem with the bitter cold just inches above them.

The flower buds on many shrubs are not as hardy as the leaf buds. This is evident every spring when we see shrubs that have flowers blooming only on the branches that were protected under snowdrift. This phenomenon will be more evident this spring. The flowers won't be there, but the plants will survive.

Tree trunks and branches last longer than branches on shrubs that are often pruned out after a few years. If your trees have been in the ground for several years, they have experienced cold like this before. The cold weather last week also helped to acclimate plants to the colder air this week. If it had been warm last week, some plant tissue may have started breaking dormancy, and that tissue would have been more likely to get freeze damage this week.

There is little that can be done to protect trees and shrubs from this cold spell. Small shrubs could be covered in snow. The biggest concern is the ones that are grafted. The desirable above-ground portion of the plant may die. If it is protected by the snow, the root stock may survive, but if it sends up new growth in the spring, it won't be the desirable plant. For instance, if your rose bush flowers change color this spring, that means the top died.

Wind chill is not a factor for plants. They do not feel colder when the wind is blowing. But the wind can be a factor in plant survival. Winter air is relatively dry. Winds can dry out stems, buds and evergreen leaves. In the spring, it won't be possible to tell if dead branches died from the cold or from drying out too much. In either case, they will need to be pruned off.

The cold will reach the southern U.S. and Gulf Coast, but these areas receive frosts and freezes nearly every winter. Gardeners in these areas know to take in tender plants and cover ones that can't be moved indoors.

Overall, the vast majority of plants won't be harmed by this cold spell. One benefit that may occur is many insect pests spend the winter tucked into cracks and crevices on tree trunks and branches. They may succumb to the cold, so it will be interesting to see if there is a difference this year.

Email questions to Jeff Rugg at [email protected] To find out more about Jeff Rugg and read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at www.creators.com.

Photo credit: at Pixabay

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