Restless Natives

With parts of the nation beset by extreme drought recently, some groups have made recommendations or enacted ordinances that seek to conserve water in their communities. To ensure that such efforts are effective, the professionals who maintain landscapes must implement water management practices based on well-founded scientific facts.

One water-saving method these organizations have endorsed is the substitution of existing landscapes with alternative plants classified either as "native" or "low-water using."

While such suggestions are always based on good intentions, they also may be ill informed, according to recent scientific studies.

Research projects by plant biologists at Arizona State University (ASU), for instance, report that in many cases the so-called native landscapes they studied receive more water than standard landscapes of turf and plants commonly identified as "high-water using."

According to one such study by Chris Martin, ASU associate professor of landscape horticulture, "native plants can survive long drought periods by shedding leaves and storing water like cacti, but they also aggressively harvest rain when it becomes available."

Martin’s research, which was funded by the EPA, found that depending on people’s water-use practices, native or desert plants, such as acacia, brittlebush, creosote bush and mesquite, could actually use two or three times as much water as flooded alfalfa, turfgrass or similar plant material.

Instead, the water-wasting culprits are the people who use improper irrigation practices and have poor landscape designs. But with well-informed water-use practices, contractors can encourage clients to save water without sacrificing aesthetic appeal.

According to WaterRight: Preserving Our Water, Conserving Our Environment, an International Turf Producers Foundation publication, contractors should use these maintenance tips to help conserve water on clients’ properties:

• Increase water infiltration by dethatching or aerating all lawn areas.

• Trim or prune trees and shrubs to allow greater sunlight penetration through and beneath the plant.

• Sharpen pruning shears and mower blades as dull blades encourage water loss.

• Perform irrigation system maintenance to ensure maximum uniformity and operation efficiency.

• Upgrade in-ground irrigation systems by adding soil-moisture meters, rain shutoff devices or ET-based controllers.

• Irrigate plants infrequently and deeply according to ET or soil-moisture requirements.

• Cycle irrigation applications to allow penetration and avoid runoff.