Don’t count on native plants to conserve water all by themselves. Plants that require little water can soak up just as much H2O as other high-maintenance varieties, according to a study conducted by the American Water Works Association Research Foundation and plant biologists at Arizona State University.
Since desert plants survive by storing water, they instinctually suck in available moisture in the soil. When homeowners douse plants like they would their traditional selections, the native plants consider the water an oasis and might absorb up to three times as much water as turfgrass, explained Douglas Fender, executive director, International Turf Producers Foundation, Chicago, Ill.
“By their nature, a desert plant survives because it has a capacity to utilize every drop of water it can reach as fast as it can,” he described. “When it is living in a desert and a rain comes along, it soaks up water. When it is in a managed landscape and people are applying water to it, it will become a water pump, in effect, and the plant will grow disproportionally fast.”
Modest brush branches into bushy trees, and then the homeowner prunes overgrown limbs, continues to water and fertilize the plant, and the cycle continues. Instead of conserving water, the plant soaks in the extra resources like vitamins and grows beyond its means.
Understanding and following maintenance routines for native, low-water-use plants will ensure they serve their purpose: water conservation. Take the Xeriscape concept, Fender compared. This landscape method, common in the Southwest, facilitates water conservation, but only if contractors follow the seven basic principles listed below.
1. Good landscape planning and design
2. Appropriate turf areas
3. Efficient irrigation
4. Use of soil amendments
5. Use of mulches
6. Incorporation of low-water-use plants into landscape
7. Appropriate maintenance of plants and irrigation systems
In other words, sound maintenance must follow planting low-water-use plants, Fender stressed. Look for signs – different for each variety – that the plant needs water. For example, leaf roll indicates water conservation in some plants, as it reduces radiant energy hitting the leaf. When contractors see this behavior, they can hold off their irrigation efforts. “Also, does the plant drop its leaves?” Fender asked. “Is that normal or is it a sign of a plant in stress?”
Bottom line, responsibility lies with the caretaker. “It’s people, not plants, that waste water,” Fender remarked.
The author is Managing Editor – Special Projects for Lawn & Landscape magazine and can be reached at khampshire@lawnandlandscape.com.