Next drought, we won't have to rely on spray paint to keep our lawns green. Or sacrifice long-loved flower gardens to stay within a water budget. Warming up to gravel groundcover instead of daisies won't be necessary, either.

At least, that's the hope of researchers at the University of California at Riverside studying irrigation and fertilizing techniques for different types of plant materials. Their goal is to provide practical guidelines for establishing mixed-plant landscapes and keeping lawns green with a minimum of water in our typically dry Southern California climate.

Since July 1993, Metropolitan Water District of Southern California has contributed $400,000 for scientists to, literally, watch the grass grow. And, of course, to tell us all how to have a healthy and pretty landscape that uses water as efficiently as possible and shows off the Southern California flair for creativity with landscape design that extends beyond sprawling lush lawns.

This information is vital to Southern California. One drop of water in every four delivered by Metropolitan to six counties spanning Ventura to the Mexican border is sent outdoors for irrigation.

According to Robert Green, turfgrass research agronomist with the Department of Botany and Plant Sciences, there are many benefits to keeping Southern California green. To a scientist, these benefits can be categorized as functional, recreational and aesthetic. For others, a green and open environment helps to balance urban pollution and give us nice places to play and daydream.

Functional benefits include dust control, flood control, enhanced wildlife habitat, cooling shade, along with reduced noise, glare and visual pollution problems. The recreational benefits are easier to see—grass is relatively low-cost and well suited to outdoor sports and leisure activities.

As to the aesthetic benefits, they include, "enhanced beauty and attractiveness, a positive therapeutic impact, improved work productivity, and an overall better quality-of-life in densely populated urban areas," Green said. He added that the turfgrass and landscape industry impacts the Southland economy and tourist business. After all, a lot here is based on appearance.

But there's more to Southern California's pretty face. We acknowledge the price for pretty.

"At the same time," Green said, "there is a need to become more efficient with landscape irrigation and develop methods and practices for utilizing lower amounts of irrigation water while maintaining landscape benefits."

At the water conservation field facility in Riverside researchers measure how irrigation cycles and plant partnering affect the well being of different species of trees, grasses and groundcovers.

One of the studies, just recently concluded and not yet analyzed, uses a grid-like configuration of 12 "irrigation cells" to see how varying amounts of water affect a lawn of tall fescue turf. For some cells, watering rates are adjusted weekly based on the prior week's evapotranspiration rate (the speed with which water leaves the soil, through evaporation, and the plant in a certain climate condition). Even with this type of irrigation, this treatment and all others were not successful in achieving a 6.0 on a scale of 9 (with 1 being worst, 5 minimally acceptable and 9 best) during all four quarters of testing.

One variable in the irrigation testing was the use of "water banking." Under this scenario, each cell received a fixed amount of irrigation water, but it was not evenly distributed over the course of the year. More water was used in the summer months, and less in the first quarter of the year. Even under those conditions, the results were the same. The grass grew greener and better from January to June than it did the rest of the year.

What do these results mean? At first glance, the study suggests that an inland valley landscape may not be able to maintain a healthy looking, stress-free lawn year-round when the landscape is 100 percent turfgrass as it was for this round of testing. Also, slow-release nitrogen fertilizers appear to be more effective than fast-release products. Although they are more expensive, the long-term water savings will pay for the more expensive fertilizer product, Green said.

Green's next study will try to answer the question of how much turf can be planted in a landscape and still maintain a healthy appearance (since the previous study suggests 100 percent turf landscaping can't work in very hot climates.) "This information will influence how landscape design is composed," he predicted.

Environmental Horticulturist Dennis Pittenger has been interested in trees for years. Since 1994, he has overseen a UC Riverside study to find species of trees that work well in inland valley areas, given a 40-foot height limit. Tree performance is evaluated with different irrigation amounts. He's narrowed down his study to 24 trees, including the Southern Magnolia, the Australian flame tree and the strawberry tree, and expects results by this summer.

"We have to recognize that water use in the landscape will be a considerable issue in the future," Pittenger said. "If we can get by on less, it's something to shoot for."

Pittenger is also interested in how well different plants perform as neighbors. He's been collecting data since 1996 on the performance of different combinations of grass, groundcover and ornamental pear trees. All possible combinations of these three, as well as individual plantings, have been watered in regimes considered optimum or minimal for turf grass.

At issue is whether growth rate is affected by different plant combinations, and what differences might occur with varying water regimes. This study will guide landscape planners on their choice of plant materials to combine with turf grass.

"Even Diamond Valley Lake (Metropolitan's 260 billion-gallon reservoir) can't provide a water supply that lasts forever," Pittenger said. "We need to learn how to irrigate in a responsible manner."

For more details about these studies, including the treatment and management protocols, or to receive the final research reports when they become available, please contact Dennis Pittenger at triscat@pop.ucr.edu and/or Robert Green at robert.green@ucr.edu .