Published on 10/19/07

Drought doesn't have to equal dead landscapes

By Faith Peppers
University of Georgia

Just because you can't water shouldn't keep Georgians from gardening this fall. You don't need a lot of water to have a lovely landscape. The secret is in the soil.

"The idea is that soil kept uniformly moist for a long period encourages the soil microorganisms to do all the work," said David Berle, a horticulturist with the University of Georgia College of Agricultural and Environmental Sciences.

"Some of the best soil out there is in areas that have been under mulch for years," he said. "I always tell people, if they have tough soil and are not ready to plant, to go ahead and lay out the bed and mulch and get the process started."

UGA horticulturist Tim Smalley said the best soil he's seen in his yard was under a decomposing wood pile. But he adds that shading and root competition have a great influence on what plants survive.

"I can see on campus that dogwoods in sun are scorched while those in shade are doing better," he said. "I lost my fothergilla competing with honey locust roots. But one in the shade of a pine looks unblemished this year."

In a previous drought, he said, "I noticed that I lost plants that were near water oaks. Last year on campus, the iteas in the sun away from the red maple were holding their own, while those in the shade of the red maples were probably suffering from root competition."

Now might be a good time to rethink landscapes and place trees such as deep-rooted oaks and pines to provide shade to plants in the afternoon or during the entire day. But beware of root competition.

"I lost all of my two- and three-year-old Hydrangea macrophyllas when I was away for five weeks during the June drought this year," he said. "However, one on the north side of the house with no root competition and receiving the water from the air conditioner condensate runoff is doing fine."

Using organic soil amendments and covering with wood chips and other mulches are proving useful in helping plants survive. Hydrogels can work wonders, too. These granules expand when soaked in water and can slowly release the water to keep soil moist. Smalley thinks they do more than that to improve the soil.

"In my research," he said, "hydrogel-amended annual beds always had larger plants than the unamended beds. Much research has shown that leaves of hydrogel plants are less water-stressed than those of untreated plants.

"However," he said, "most scientists believe that the improved growth and water relations are caused by increased root growth prompted by the hydrogel products. Hydrogels continuously expand and contract with the availability of water, and this expansion and contraction continuously tills the soil and improves the soil environment for root growth."

Gardeners who feel at a loss when considering landscape needs this fall aren't alone. Planning is paramount, and even the experts are seeing things differently.

"I'm considering making some changes in my landscape plans," Berle said. "I was already planning to swap out some plants. But this summer has convinced me to be more mindful of plant and water needs."

Faith Peppers is the director of public affairs with the University of Georgia College of Agricultural and Environmental Sciences.