Ornamental Field Day Held at E.V. Smith Research Center

SHORTER, Ala.— Can the ornamental life of flowering kale and cabbage be extended using growth retardants? Can a new product help control root growth in urban landscapes? What landscape environments promote cockroach infestations?

These and many other questions concerning landscape management in home and urban settings were addressed during the Home Landscape and Ornamentals Field Day held recently at the E. V. Smith Research Center in Shorter.

More than 80 people attended the Field Day that featured the latest results of research conducted at the Research Center, the main research facility of the Alabama Agricultural Experiment Station at Auburn University.

Flowering kale and cabbage are popular cool-season annual landscaping plants, according to Gary Keever, a horticulture researcher at Auburn University. But their usefulness in landscapes is often cut short when the plants "bolt," or produce stems that will eventually form flowers and seed.

The hormone that causes bolting can be inhibited by commercial chemical growth retardants, which are sometimes used on other ornamentals to produce small, compact plants. Keever theorized that these chemicals might delay bolting in ornamental kale and cabbage, thus prolonging the plants' usefulness in landscapes. He tested this idea by applying Sumagic(R) growth retardant to flowering kale and cabbage planted at the Center. Sumagic is not labeled for use on these plants.

Early results from this study suggest small amounts may be useful in delaying bolting. "We are now recording growth and date of bolting," he said of the project. "The study will probably be repeated next year to refine treatments before this technology can be useful for homeowners and landscapers."

Another project underway at the Research Center is exploring ways to control tree root growth in urban landscapes. Charles Gilliam, also an Auburn horticulturist, explained that tree roots often buckle sidewalks and invade septic lines. But a product developed to keep roots out of hazardous waste dump sites may help control this problem.

This product, called Biobarrier(TM), is a polypropylene woven fabric that has been treated with Treflan(R) herbicide. The herbicide keeps roots from passing through the liner. Gilliam and other researchers have been comparing Biobarrier to a standard weed mat.

After the first two years of growth, the study has shown that an average of one root per tree penetrated the Biobarrier, while as many as 100 roots per tree had penetrated the weed mat.

"This indicates tremendous suppression of root growth by Biobarrier," said Gilliam. While these results look promising, Gilliam noted future results will help determine if the barrier is effective for long periods of time and if there are any ill-effects on long-term tree growth.

"We have measured growth of the tree annually and have found no difference in tree growth during the two years of the study," he noted.

Peridomestic cockroaches, cockroaches that usually live outside but can become pests in homes, were discussed by Art Appel, an Auburn entomologist. Using a high-tech computerized cockroach habitat located at the Center, Appel has been evaluating various mulches and landscape situations to see which ones promote or inhibit cockroach infestations.

The study has shown that cockroaches thrive in straw and grass environments, but do poorly when living on bare soil, ornamental gravel and other environments where temperature and moisture conditions are unsuitable for cockroaches. These results suggest that pine straw and other straw mulches placed near houses may promote the spread of these cockroaches into homes.

Additional topics covered on the program included information about several recently-instituted projects at the Center. Among these are performance evaluations of cool-season annuals, such as pansies, snapdragons, dianthus and flowering kale and cabbage; the control of blackspot on roses; and the use of lawn debris for mulch in home landscapes.

Other program participants included: Bridget Behe, Fred Deneke, Bill Goff, Joe Eakes and Dave Williams, all researchers working in Auburn's Department of Horticulture; Kira Bowen and Becky Young, both of Auburn's Department of Plant Pathology; and Walter Hogue, superintendent of the Horticulture Unit at the Center.

Jim Bannon, director of the Center, explained that E.V. Smith is one of only a few research centers in the Southeast conducting this type of research. He urged those attending to come and visit regularly and keep up with the projects.

David Teem, associate director of the Experiment Station, noted that these types of studies have only been underway at the Center for about three years. He requested feedback from visitors about current and future studies.

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News from:

Office of Ag Communications & Marketing

Auburn University College of Agriculture
Alabama Agricultural Experiment Station
3 Comer Hall, Auburn University
Auburn, AL 36849
334-844-4877 (PHONE) 334-844-5892 (FAX)

Contact Jamie Creamer, 334-844-2783 or jcreamer@auburn.edu
Contact Katie Jackson, 334-844-5886 or smithcl@auburn.edu

March 3, 1992