SOUTH CENTRAL TEXAS – As more persistent cold weather blankets South Central Texas, many of the region’s residents are becoming increasingly concerned about protecting household plants, according to area horticulture experts.
“We’ve been getting a lot more inquiries from people about what steps they can take to keep their plants from being either damaged or killed by freezing or near-freezing temperatures,” said David Rodriguez, Texas AgriLife Extension Service agent for horticulture in Bexar County. “What many people in this region don’t realize is that many popular plants in this area can be damaged without a hard freeze or even at temperatures several degrees above freezing.”
Rodriguez said South Central Texas residents have become used to the milder winters of recent years which have averaged only about six frost days during the season.
“But it’s wise to remember that there’s really no such thing as a typical winter, and there may be 24-hour periods when the temperature may drop as much as 40 degrees. The time will come when you have to protect your plants.”
He added that container-grown plants are more susceptible to cold damage because their roots are more exposed.
Daphne Richards, AgriLife Extension county agent for horticulture in Travis County, added that popular South Central Texas plants such as bougainvillea, as well as other tropical or semi-tropical plants can be damaged by temperatures still several degrees above freezing.
“Bougainvillea is one example of a plant that’s popular in this region but is not especially cold tolerant,” she said. “Neither are most types of hibiscus plants.”
Richards added that due to generally mild winters in the past, South Central Texas residents have begun using plants native to arid desert regions, which makes them more drought-tolerant, for their landscaping.
“But people need to recognize the difference between high deserts and low deserts,”she said. “Low deserts, such as the Sonoran Desert in Arizona, have very mild winters and warm nights. High desert regions, such as the Chihuahuan Desert in far West Texas and New Mexico, have colder nights and freezing winters. So when choosing desert species, people should look for high-desert natives.”
Richards said that the common non-variegated American agave, angustata – a hardy variety of esperanza – and the aptly named hardy “ice plant” would fare better in colder weather, as they are adapted to colder winters and freezing temperatures.
“Of course, people in South Central Texas wanting to plant cold-tolerant winter annuals for color can do well with pansies and cyclamen,” she said, “but these won’t be able to handle our summer heat.”
“In the springtime, people who are concerned about their landscaping surviving lower temperatures in the late fall and winter might also do well planting perennials, sages, hollies or the like during the spring,” said Jim Strong, a member of AgriLife Extension’s Bexar County Master Gardener volunteer horticulture organization. “But it’s often a matter of degree – or degrees – on whether even more cold-tolerant plants will survive, especially if there are several days in a row of below-freezing temperatures.
There are, however, a number of things South Central Texas residents can do to help “winterize” their plants, the experts said. Some tips included:
– 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 do not need to be moved, except in the case of prolonged, severe freeze.
– Cover plants with plastic film only in conjunction with 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 coverings drape all the way down to the ground and are adequately secured with rocks, boards, bricks or soil in order to keep the wind out and allow heat retention.
– Before freezing temperatures occur, water plants thoroughly 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 and retains the moisture that keeps plants warmer.
– Consider a “hoop tunnel” or other covered structure and place open jugs of water inside of it to add heat through moisture.
– If you own a greenhouse, make sure it is airtight, protect water pipes and connections from freezing, and remove any shading material until spring. If practical, add another layer of polyethylene plastic, keeping at least an inch of air space in between the layers to maximize warmth. Flooring materials such as stone, gravel, brick or rock will help store heat, so soak the floor frequently with water.
Additional gardening tips can be found at the Aggie Horticulture Web site: http://aggie-horticulture.tamu.edu .
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