Choosing, preparing plants for winter
Now that Old Man Winter is here, South Central Texas residents need to be even more aware of ways to protect their plants from from his icy grasp, according to a Texas AgriLife Extension Service expert.
"Daily low temperatures in this region have been dropping to freezing or near-freezing, so it's a good time for people to be aware of steps they can take to help ensure plants aren't damaged or killed as temperatures continue to go down," said David Rodriguez, AgriLife Extension agent for horticulture in Bexar County. "And what people don't realize is many plants here can be damaged without a hard freeze and even at temperatures above freezing."
Rodriguez said South Central Texas residents have become used to milder winters in recent years, but should understand "there's really no such thing as a typical winter" and that it's not unusual to have 24-hour periods during which the temperature can drop as much as 40 degrees.
"Container-grown plants are more susceptible to cold damage because their roots are more exposed," he said. "And many plants popular with South Central Texas residents, such as bougainvillea and hibiscus, as well as other tropical or semi-tropical plants, can still be damaged by above-freezing temperatures. Knowing your plants can help you better understand what you need to do during the winter to protect them."
There are a number of steps South Central Texas residents can do to help "winterize" their plants, Rodriguez said. These include:
--Bring plants indoors or move them into a protected outdoor area, such as a covered patio, under the eaves of the house or near the base of a large tree. Extra-hardy plants, such as Dwarf Yaupon holly, Dwarf Burford holly, aspidistra (cast-iron plant) and nandina need not be moved, except in the case of prolonged, severe freeze.
--Cover plants with plastic film only if an added layer to other wrapping materials such as burlap or cloth. During cold weather, plant tissue can "burn" wherever it comes in direct contact with plastic.
--Make sure plant coverings drape all the way down to the ground and are adequately secured with rocks, boards, bricks or soil to keep wind out and allow heat retention.
--Water plants thoroughly before freezing temperatures occur as moist ground stays warmer than dry ground.
--Use mulch to protect lower stems and roots from cold. Mulching provides an extra layer of protection that helps plants retain moisture and stay warmer.
--Consider buying a hoop tunnel or other covered structure for plants and place open jugs of water inside to add heat through moisture.
--Make sure greenhouses are airtight and remove any shading material until spring. If practical, add another layer of polyethylene plastic and keep space between the layers to maximize warmth. Soak the greenhouse floor frequently to keep it moist.
Rodriguez said in preparation for the possibility of colder future winters, people may want to consider planting more cold-tolerant plants.
"Many South Central Texas residents are landscaping with plants more native to arid desert regions, which makes them more drought-tolerant," he said. "But for cold tolerance it's best to use plants native to the high desert region, such as the Chihuahuan Desert in far West Texas and New Mexico, as these places have colder nights and freezing winters the plants have adapted to as well."
Rodriguez said plants such as the common non-variegated American agave, angustata--a hardy variety of esperanza--and the aptly named "hardy ice plant" do well in colder weather.
"And if you want to plant some more cold-tolerant winter annuals for color, you may want to consider pansies and cyclamen. However these probably won't be able to handle the Texas heat when summer rolls around."
During the spring, people who are concerned about their landscaping surviving lower temperatures in the late fall and winter might do well planting perennials, sages or hollies, he added.
"Of course even with more cold-tolerant plants it can be a matter of degree--or maybe I should say degrees--as to whether the plant will survive, especially with several days of below-freezing temperatures in a row, so you may need to take extra measures to protect these plants too."
Additional gardening tips can be found at the Aggie Horticulture website at http://aggie-horticulture.tamu.edu.