The Curse—and Opportunity—of the Uncommon Cold

John Johnston
Every so often, a new weather record is broken in your state. Whether it’s rainfall, snowfall, drought and/or frigid temperatures, it’s going to happen.

As I write this tip, I recall a winter long ago that was so cold, the Delaware River froze and you could attempt to walk from Camden, New Jersey, to Philadelphia! This year we saw the Polar Vortex come and go throughout the Midwest and East Coast. Read on to prepare for the challenges and the opportunities that may lie ahead in spring 2019.

From Bone-Chilling to Silver Lining

Extreme temperature swings can cause major damage to plants and shrubs, especially those planted in regions where consumers cheated the hardiness zones. Only time will tell whether plants will respond to warming temps this time around.

Winterkill from the record-setting arctic blast of January 1985 eliminated nearly an entire collection of roses at Hershey Gardens in Pennsylvania. With sustained temperatures dipping into negative numbers throughout the eastern United States, we saw the impact of losing well-established plants everywhere.

In contrast, 1985 turned into a good year for nursery sales, as consumers shopped for replacement plants. Maybe this year’s bitter cold will yield another opportunity for sales and profits when spring arrives.

From Slumber Party to Garden Party

Pruning is among the many routine tasks of springtime. Most consumers are unaware of its necessity and its benefits, which presents you with an opportunity to educate. By eliminating deadwood and branches, the growth of the plant is replenished by pushing new basal breaks from the crown of perennials and roses. New buds will emerge from branches and canes, and the strength and energy of the plant is concentrated into a smaller area.

Two types of pruning methods pertain to plants, especially roses. First, is a reduction in size by cutting the canes to the desired height while eliminating crossing canes. These canes are cut about a ¼ in, above an outward facing bud eye. The second part of the process is to eliminate dead wood or blackened canes. After a prolonged winter with extreme temperature shifts and high winds, consumers may need to prune these canes right down to the rose crown or bud union, where the canes start.

In situations where extreme pruning is needed, plants may take a while longer to produce roses the following spring. They’ll be rewarded with an eventual flush of new blooms sometime between Mother’s Day and Flag Day, depending on the variety and your location.

An Ounce of Protection, a Pound of Prevention

Any cut into the pith of a branch or cane can become a new point of entry for insect borers or disease. It’s wise to seal these cuts using a suitable pruning sealer. However, I caution against using a pruning sealer on rose canes. Many contain petroleum distillates, which may damage soft and sensitive tissue. Instead, advise your customers to use Elmer’s Glue, nail polish or orange shellac on these tips.

Remind consumers to examine trees for similar damage, such as branches that have slightly broken away from their trunks from the weight of ice and snow. If a compromised branch fully leafs out, it may produce enough weight to splinter away from the trunk. Clark’s Grafting Wax and binding tape may help salvage the branch; be sure to have these products on your shelves as spring arrives.

The Day the Earth Moved

Frost heaving is a common occurrence during the extreme temperature swings of winter. Water and moisture can expand during winter months and, in some cases, sever roots around trees and plants. No worries! It only takes a springtime feeding of organics or the addition of a root stimulant or mycorrhizae to produce new feeder roots to sustain the plant. To speed the process along, ask your customers to consider the addition of a soil amendment or top dress of mulch to increase moisture availability. GP

John Johnston is Retail Education Manager for Griffin. He can be reached at jjohnston@griffinmail.com.