By Sharon Omahen
University of Georgia
Covering outdoor plants with blankets and plastic to protect them from the cold may make you feel better, but chances are it won't keep them cozy.
University of Georgia horticulturist Orville Lindstrom says although it's been done for years, giving your outdoor plants a blanket won't keep them warm unless you find a way to anchor it.
"Even if the covering stays on, a blanket on a plant isn't going to create heat as it does on a person," Lindstrom said. "We're warm- blooded, and we create heat. Plants aren't. The only heat available under the blanket would be coming from the soil."
Even if covering did work, Lindstrom says the wind usually works against your efforts by blowing your hard work away. Plus, using a blanket to cover your plants can also result in broken limbs.
"The added weight of the blanket can put pressure on the limbs and cause them to break," he said. "You have to weigh the risks. If you put up a large enough structure that will block the wind, it would help. But then you've all but built a mini-greenhouse."
Other ways to help
If you really want to help your outdoor plants prepare for the cold, Lindstrom says the time to help is actually in the spring and summer.
"If you take good care of your plants in the warm months by keeping them insect-free, giving them ample water and fertilizing them," he said, "you're helping build a hardier plant."
Because outdoor plants are out in the elements 24 hours a day, they adapt to temperature changes.
"When winter arrives, it's not a shock to them because they have gradually prepared for it," Lindstrom said. "Temperatures would have to drop below 20 degrees to damage the stem tissue of landscape plants. And I haven't seen that happen in the South."
Baby the special ones
If you want to "baby" your plants, save the special treatment for prized possessions such as a banana tree, he said. If it's a one- of-a-kind plant and you really don't want to lose it, build a makeshift shelter for it.
Lindstrom says container plants are the ones that need the "babying treatment."
"Container plants are especially susceptible to cold temperatures," he said. "Their roots are more exposed to the cold because they are above ground."
You can protect your container plants several ways. Place them inside your home, garage, greenhouse or shed. You can also push container plants together and mulch or cover the sides of the containers to decrease heat loss.
Plants growing close to the ground usually benefit from the heat radiating from the soil, he said. "Tall, more open plants don't receive as much heat and are not as protected from the cold," Lindstrom said.
Time will tell
You won't truly know whether your protective efforts were successful until warmer weather arrives. Plants with cold-damaged roots may not show signs of injury until temperatures rise and the plant's demand for water from the roots is greater, Lindstrom said.
The overall key to making sure your landscape plants survive each winter is planting the right variety from the start.
"Don't just buy a cultivar of azalea or other woody ornamental you've heard about or one you think would do well in your landscape" he said. "Do a little research and make sure the plant you're buying is suited to your area. Then you can save your blankets for keeping your family warm."
(Sharon Omahen is a news editor with the University of Georgia College of Agricultural and Environmental Sciences.)