Researcher determines water requirements for native plants
By Jenna Smith
For more information regarding this subject, contact:
Keith Owens
(830) 278-9151
m-owens@tamu.edu
Woolly Butterfly Bush, Mexican Bush Sage and Evergreen Sumac ranked among the lowest water-users in a recent study of native shrubs and trees in South Texas. Although xeriscaping-a technique that uses water-efficient native plants-has been around for some time, actual water requirements of many popular native plants have not been available until now.
Through the Rio Grande Basin Initiative, Keith Owens, professor of range ecology at the Texas A&M University Agricultural and Research Center in Uvalde, is investigating the water use, fire ecology and landscape ecology of South Texas trees and shrubs.
“The use of native plants in landscaping has become a rising trend in Texas,” he said. “Native shrubs as a whole are very low maintenance, demand very little pruning and supplemental water, and are resistant to pests and diseases.”
Yet, Owens said xeriscaping is not used as widely as it should be. “We are trying to promote the practice to save water,” he said. “Homeowners don’t utilize the full potential of this drier landscaping tool. Too many times they overwater low water-use plants, defeating the purpose of xeriscaping.”
Owens’ study focuses on determining the minimum amount of water that these native plants can utilize while still maintaining attractive flowers and foliage.
“For most of these shrubs, the worst thing you can do is over-water,” he said. “All of the plants we used are adapted to high light environments.”
Owens selected the varieties of ornamental trees and shrubs after talking to specialists with Texas Cooperative Extension and local nurseries throughout the Rio Grande Basin.
“Native shrubs are obviously adapted to the area and can persist without human intervention,” he said. “We wanted to select shrubs with either flower or foliage characteristics that would be attractive in landscapes.”
The study uses12 species of trees and shrubs to determine specifically how much water is used by nursery stock. All of the potted plants were borrowed from local nurseries.
Based on the results, homeowners needing a landscaping shrub with limited water uptake are advised to use the Woolly Butterfly Bush, which only needs 0.04 gallons of water per day. Crape myrtles, on the other hand, one of Texas’ most widely used landscaping trees, require the most water, 0.21 gallons per day.
Owens will present his information and offer recommendations to the public through printed material. More information can be accessed through his Website at http://uvalde.tamu.edu/ornamental/index.htm.
The shrubs used in this study are native from the Uvalde area south to the border, so homeowners in this region can locate any of these trees or shrubs at a local nursery.
Owens is also conducting a follow up experiment that addresses the actual water use of mature plants rather than nursery stock in a landscape setting. The field experiment uses a sap flow system that measures the amount of sap (or water) flowing through the stem on a continuous basis. These results will be applicable to landscaped gardens throughout the South Texas region.
