Last week, I presented an article on protecting your plants for winter. I promise at some point we will experience cold weather for an extended period of time. Seems overall the late summer and early fall has been a little drier and warmer in the area.
This week, I would like to continue on this topic and add more information in this area. There is nothing more disappointing than to be dedicated to your plants and try to have a nice looking landscape, but due to a few mistakes have cold damage the following spring.
I will be sharing information from a UGA publication by Bob Westerfield, a UGA Extension horticulturist, and Orville Lindstrom, a professor of horticulture.
For a quick review, last week we talked about the importance of cold acclimation. This is simply the preparation time by plants to get ready for winter. This process is brought on by cooler temperatures and shorter days. Plants can have cold injury on the fruit, stems, leaves, trunk and roots.
You can go back to the article from last week on the types of damage. We discussed the importance of proper plant and site selection in the beginning plus proper plant nutrition to help in reducing cold damage.
Fertilizing at the suggested time is important. For example, fertilizing plants in the fall with a high nitrogen fertilizer can cause more new growth that can be set up for a greater chance of cold injury.
We also talked about pruning at the correct time. Pruning in the late summer and early fall can stimulate new growth that will be at a greater risk of cold damage. Much of our cold damage may be associated with that improper pruning time.
If you wait too late in the fall or early winter to transplant items that can be a problem too. Plants do not prepare to cold weather correctly so more problematic to cold weather too if transplanted too late in the year. Transplant early in fall.
Finally, we talked about canopies and shade in regards to ornamentals. This is due to reducing radiant heat loss that you can see on those cold, calm and clear nights. Windbreaks such as fences or buildings can also help in protecting ornamentals.
Another thing to consider in protecting your plants from cold weather is covering or heating. Many people will grow plants in containers. If you can move the containers, you can move the plants into your home, garage, greenhouse or an outdoor shed.
I remember when I worked in Bartow County, one family grew very large cactus in containers. They would have to put these massive plants and large containers into their garage each year. It was a lot of extra work, but they really enjoyed their plants.
The big issue with container plants is exposed roots. Remember, the roots are not in the natural ground while in containers. The roots are in containers that are more exposed to cold air so more susceptible to cold injury. If roots are injured, they may not show signs soon. Their damage may be seen when temperatures rise and the water demand increases because of root damage. One way to reduce injury is to push together container plants that you keep outside and mulch or cover them to reduce heat loss.
You can also wrap the base of the containers with items such as plastic, burlap or blankets to reduce heat loss. This may be common sense, but plants growing close to the ground are more protected by radiant heat than a taller plant.
Mulch can assist by reducing soil heat loss. Mulch can keep soil temperatures more uniform. If you choose to cover your plants when cold weather is on the way, the material you use is important. Try to use sheets, blankets or even cardboard boxes. Our information does not recommend plastic as a covering option. The plants can heat up too quickly when using plastic and damage the plants.
When using a cover, remove the cover during the day to let the heat release that was trapped by solar radiation, according to our information. You can build a frame for your cover to keep the material from touching the plants. That would just take more effort.
We forget about this, but plants have water requirements even during winter months. Proper irrigation practices will help keep a plant cold hardy. Water a plant prior to a cold snap if necessary. Keep in mind that moist soils absorbs more heat so it helps to keep an elevated temperature around the plant area. You can also mulch the base of the ornamental to help conserve soil moisture.
Greg Bowman is the Gordon County Extension Agent. For more information, contact UGA Extension – Gordon County at 706-629-8685 or email email@example.com.