Warmest Winter - What Can It Hurt?

Six days in December reached high temperatures of 50 degrees or higher. Christmas day reached 53 degrees! Dubuque has seen the warmest February on record. Both February 26th and 27th set records of 72 degrees.

We humans didn’t mind at all, in fact we loved it. The traditional winter months seemed short, except for that 2-week period in mid-January when we received 20+ inches of snow and the temperatures plummeted to 17 degrees at one point. Above ground woody plants not so much! Given the fact that different plants and different plant parts can have different freeze tolerance, they all go through a cold acclimation process developing their winter hardiness. This process begins in the fall as the days become shorter and the temperatures continuously drop. By mid-winter, the maximum freeze tolerance is reached. How does this happen you say? A simplified short version is as follows. During this process, moisture within the woody cells moves out of the cells into a gap in-between cell walls, where if it freezes, it does not damage the cells themselves. As this happens the loss of moisture within the cells concentrates the sugars that are left behind creating an antifreeze.

Here-in lies the problem. When we get a string of balmy warm weather, a declamation process begins and freeze tolerance is lost. If temperatures drop suddenly, and to a great degree in a short period of time, freeze damage may occur and bark damage and/or stem cracking may result.

Here in The Midwest, it is estimated that spring-like temperatures have arrived as much as 20 days earlier than considered normal. Many trees and shrubs began to bud out leaving them vulnerable to late spring freezes and frosts. How this will affect the plants remains to be seen. We have not experienced these conditions before to know fully what the result will be. It will all depend upon the stage of development, bud type (flower or leaf) and low temperatures reached.

A temperature of 28 degrees can be damaging, 25 degrees and below even more so. Ornamental fruit trees and magnolias may not produce an abundance of flowers this year. Some leaves may brown out early or have holes in them after they have fully developed. It is interesting to note that leaves within the protective bud scales are fully formed. If the bud tips get damaged, the holes will show up as the leaf fully unfolds in its development.

Flowering trees, especially fruit trees, may experience significant flower loss resulting in fruit and seed loss. I for one won’t mind if the Silver maples in my back yard didn’t produce an abundance of seeds this year! Spring, summer, and fall are not the only seasons when trees and shrubs have something to offer.  We anticipate the swelling of buds and seeing the first robin, telling us that spring has arrived. We enjoy the fragrance of developing flowers, and the renewed development of leaves and needles. Suddenly, all is fresh and alive!

As summer arrives, we appreciate the cool shade and rustling leaves. We delight in the birds and squirrels as they move about.

Perhaps the most enjoyable season is in the fall as trees make preparation for dormancy and the long winters cold. Who hasn’t gone on a fall foliage drive into the country, between the hills, and along the river roads. Nothing seems as magnificent as the leaves are turning color. Every year is just a little bit different, but never seems to disappoint.

So, what does winter have to offer? Now that the flowers and leaves are no longer capturing our attention, for many of us, our eyes are drawn to interesting bark colors, textures, and patterns.  Remaining fruits, berries, seeds, and cones add a little decorative color. Of course, all of this beauty is enhanced by fresh fallen snow, especially on needled evergreens and the sight of a pair of cardinals.

Bark provides many interesting features. The following are some of my favorites and may be some of yours too: River Birch has a creamy cinnamon exfoliating (peeling) bark, Shagbark Hickory has shaggy looking bark in long strips, Hackberry trees have a corky and pebbly texture, Beech trees have a smooth silvery bark, Kentucky Coffee tree has a plated and furrowed bark, Bur oak and Blue Ash have a winged or deeply furrowed corky bark on their branches. Several evergreens have reddish brown peeling bark in long strips. Some shrubs have stems of yellow or red like that found on the Red and Yellow Twig Dogwood.

Some trees produce seed pods. Catalpa pods are long and slender, while the pods of Honey Locust are brown, flat, and twisted. Kentucky Coffee tree pods look similar but are not as long or twisted. Black Locust and Red Bud trees have much smaller and thinner pods.

Ornamental Crab trees have red, yellow, and purplish fruits in various sizes. These fruits are called persistent, because they last until early spring, and often eaten by birds before they have a chance to fall from the tree.

Several shrub varieties produce colored berries along with several evergreens. The Common Yew produces red berries while Junipers are a silver blue. Red Chokeberry, Holly and Winterberry produce red berries while Japanese Barberry produce small red berries in clusters. Mountain Ash has clusters of orange berries and Black Chokeberry have black berries.

A walk in the woods, around our home landscapes or a visit to a local arboretum in the winter can be very pleasing. Many ornamental grasses and perennials enhance this experience.