Florida-Friendly Landscapes: When less (irrigation) is definitely more (water conservation)

Usually, the conclusions follow the research, but not so for the water conservation benefit of Florida Friendly Landscaping (FFL). The FFL program  has been touted as a method for conserving water (Florida statutes agree), but before our recently published study, no peer-reviewed published research existed documenting the actual water conservation of FFLs.

The FFL program promotes environmentally sustainable landscape practices. Recognized FFLs usually have more ornamental plants and less turfgrass, although there is no restriction on the amount of grass allowed. There are nine principles to  a recognized FFL, and the second principle “water efficiently” is the focus of our research. The FFL recommended practices for water conservation include:

     • Irrigating turfgrass and ornamental plants separately,
     • Grouping plants with similar water needs,
     • Reducing irrigation in the rainy summers and mild winters, and
     • Having a rain shutoff device for a sprinkler system.

Xeriscaping, a somewhat similar landscape approach, has been shown in research studies to reduce irrigation in the arid southwest. Although both FFL and Xeriscape have the same goal of conserving resources, they are designed for very different environments (both in terms of growing conditions and aesthetics). Additionally, FFL encourages wildlife habitat creation and protection whereas Xeriscape focuses primarily on water conservation.

L to R: Comparing perennial peanut to cacti - Florida-Friendly and xeriscape examples

For our study, we visited FFLs in Hillsborough, Pasco, and Pinellas counties in southwest Florida, evaluating 125 FFLs and identifying 736 comparison (well-maintained, turf-dominated) landscapes. All landscapes were part of single-family residential homes and used potable water for irrigation. We used up to twelve years of monthly water billing records for each home and property appraiser data to estimate each home’s monthly irrigation use, and we used daily weather data to estimate the monthly irrigation required (how much each home should have been watering). Once we began our site visits, we realized that just because a landscape was recognized as a FFL doesn’t mean that it’s still maintained as a FFL, or is a landscape that we would want to replicate. FFLs were classified as either good (well-maintained, diverse plantings) or not-so-good (well-maintained but not exhibiting FFL characteristics, or poorly maintained).

Recognized FFLs: The Goods

Recognized FFLs: The Not-So Goods

For the comparison landscapes, we rated the turf on a scale of 1 to 9, with minimally acceptable turf for our study being 6. The landscape quality of the comparison homes varied, from slightly patchy and yellow-green to beautiful green carpets of high-quality turfgrass you could take a nap on.

Comparison homes: Not all turfgrass is created equal

Our analysis of estimated irrigation use indicated that FFL homes used 50% less irrigation than comparison homes, and irrigation savings were seen in every month (shown in figure below). At least half of all monthly irrigation values were zero, meaning that a large portion of both FFLs and comparisons did not use in-ground irrigation systems or water regularly. Both landscapes were irrigated less than what was required for well-watered turfgrass.

When considering only “Good” FFLs and their comparison landscapes with high-quality turfgrass, irrigation savings increased to 76%. Comparison homes’ irrigation exceeded the irrigation required for well-watered turfgrass in the winter months.

Before becoming FFL-recognized, the FFL homes already used less irrigation than the comparison homes did, meaning that those most concerned with water use were more likely to choose a Florida-Friendly Landscape. Even though they tended to already be low water users, FFL homes reduced their irrigation use 28% after their landscapes became recognized.

The results of this study demonstrate the ability of FFLs to conserve potable water used for irrigation. A follow-up study will survey FFL and comparison homeowners so we can better understand how the irrigation savings are being achieved.

Thanks to Southwest Florida Water Management District and Tampa Bay Water for funding this project and to Michael Gutierrez and Sara Wynn for their assistance. This study was co-authored by Michael Dukes, Linda Young, and Shu Wang.

About the author

Mackenzie Boyer is a Ph.D. candidate in Agricultural and Biological Engineering at the University of Florida. She studies residential irrigation using utility water billing data. Her two dogs undermine all her efforts to keep her own lawn looking presentable.