Play IT Smart

It’s not too early to begin thinking about the effects of cold weather on the landscape. As a matter of fact, on average, the first killing frost for our area is usually during the middle of November.

Many of the plants we have in our landscapes in Northwest Florida can be damaged by cold weather. Some of this damage can be reduced or possibly prevented when the plants are maintained correctly. There are some things you can do now to prevent some winter injury in your landscape.

First, you should strive to keep your landscape plants healthy. This includes: trees, shrubs, and turf. Avoid letting the plants become stressed from lack of water, poor fertility, etc. When plants are weakened, they are more susceptible to disease and insect attack. This weakened condition will make them less likely to survive the winter months.

For most trees, shrubs and warm-season turf grasses, it is best to avoid fertilizing with a high nitrogen fertilizer too late in the year. Generally it is best to avoid using a high nitrogen fertilizer any later than September. Nitrogen can force the plant to begin growing too late in the year. That new tender growth is very susceptible to cold injury.

Because pruning will also cause plants to produce new growth, it is best to avoid pruning most trees and shrubs during the fall. Usually a few weeks after pruning, a plant will begin producing new growth. This new growth is subject to cold injury.

Two to three inches of mulch, such as fall leaves or pine straw, over the plant’s roots will also help. This may not help in extreme hard freezes, but it may delay the freezing of the soil, allowing the plants to continue to draw up the water they need.

In general, shorter days, cooler temperatures and frosts are nature’s way of more water around the roots, allowing more water to be taken up into the plant itself. And because freezing has a drying effect on plant tissue, the extra water will reduce this type of injury.

In addition, a moist soil traps more of the sun’s energy and releases this energy at night, providing some warmth for the plants. Use a garden hose to direct the water to the base of the plant and try not to wet the foliage.

Plants that are exposed to high winds may be protected from cold injury with some kind of windbreak. The purpose of a windbreak is to prevent the cold winds, which have a drying effect on plants, from hitting the plants.

Here again it is questionable whether or not windbreaks are beneficial in hard freezes. There is strong evidence, though, that plants in protected areas survive extreme hard freezes.

During mild freezes, covering tender plants with a sheet or blanket may spare them from injury. For these coverings to be effective, they must cover the plants completely, making certain that the covering goes all the way to the ground and that the sides are held down with soil, brick or stone. The covering will trap heat from the soil and hold it during the night.

One word of caution: The covering should be removed when the temperatures rise above freezing the next day. The reason for this is to prevent the plant’s dormancy from being broken, making it more susceptible to cold damage.

Plastic coverings, on the other hand, aren’t recommended because they offer very little protection from freezing temperatures and because they allow a rapid temperature buildup under the cover when the sun rises. The high temperature may cause the frozen plants to thaw out too quickly, causing severe injury to the trunk and stems.