Reining in Water Use
Ground rules for creating a lush yard that doesn't squander the available supply of H2O
In this drought-tolerant Santa Monica, California, backyard, landscape designer Nicole Lopez cut the lawn back to a rectangle just big enough for lawn sports and kids' play. Then she surrounded it with low-water plants that saturate the space with color and texture.
Introduction to Xeriscaping
Here's a riddle for you: Two homeowners live on the same street. One sprinkles his lawn weekly with massive quantities of bottled water. The other hooks his hose up to an oscillating sprinkler each morning and then cascades the driveway, adjacent pavement, and passersby with the town's finest tap water. Who's being more extravagant?
The answer isn't so easy to figure in drought-prone places like Santa Monica, California, where rainfall measures a scant 12 inches a year and 90 percent of the municipal water supply has to be imported from sources 400 miles away. Not coincidentally, "irrigation overspray" and watering lawns between the hours of 10 a.m. and 4 p.m., when moisture evaporates most quickly, both violate the city's municipal code.
"Where drinking water is scarce, it doesn't make sense to use so much of it on our lawns and flowers," says Santa Monica landscape designer Nicole Lopez. "You need to match plants to the climate that you live in. It just doesn't work the other way around."
The idea of creating a landscape designed to thrive on the amount of rainfall nature provides—called xeriscaping (ZEER-uh-scaping)—seems like a no-brainer when you consider the facts. Across the country, booming populations of homeowners are siphoning off reservoirs of potable water faster than clouds can replenish them. The problem spikes in summer, when, depending on rainfall, anywhere from 30 to 60 percent or more of all residential water used gets lavished on the landscape.
Wherever you live, it makes sense to stretch the finite supply of drinkable H2O as far as it can go. Water-wise landscapes tend to be more resistant to diseases; more welcoming to pollinating butterflies, birds, and bees; and easier to maintain. All good news, whatever the weather report predicts. Using water resources wisely doesn't mean you have to give up turf grass cold turkey or resign yourself to a gravel garden. While soil types, annual precipitation, and recommended plants differ from region to region (and even yard to yard), the basic principles that Lopez applies to sustain landscapes in perpetually water-strapped Southern California will help you create a yard that will weather dry spells, too.
Rain-permeable ribbons of crushed stone divide 4-by-6 foot concrete pavers that form the pathway, which was raised 4 inches above grade to encourage water to run to, and penetrate, planting areas.
Shrink the lawn. Most turf grasses require at least an inch of water a week to stay green in summer. So think about how much lawn you really need. When the owner of the Santa Monica property shown on these pages expressed his desire for a patch of turf where he could enjoy weekend volleyball games and where friends' toddling children could play safely, Lopez let form follow function, sculpting out a generous swath of sprinkler-irrigated lawn, then surrounding it with groundcovers and ornamental plants better suited to the local hot, dry weather.
Plant for your climate and site conditions—living things thrive best where they feel most at home. That can mean researching and putting in species native to the area, or ones that thrive in similar climes. Lopez's designs mix resilient Southern California natives like agave and Dudleya edulis (both succulents) with plants from places where conditions are similar, including Mexico, the Mediterranean region, South Africa, Chile, Australia, and arid parts of New Zealand. Be mindful of how much sun and shade your yard receives—and the potential of any plant you choose to be invasive.
Address drainage issues early on. Before planting, test your soil by digging a hole, filling it with water, and seeing how long it takes for the water to percolate out. Clay-heavy soils that are slow to release moisture will suffocate plants. Soils that are sieves—overly sandy or hard and nutrient-poor ones, for example—fail to give plant roots a chance to drink up available water before it runs off or seeps out of their reach. Once you know what type of soil you've got, you have two choices: Try to find plants that like it the way it is, or amend it to improve the way it drains. Adding peat moss and aged compost will help beef up poor soil; incorporating sand along with compost will loosen clay soil and improve drainage.
Irrigate effectively. The most efficient systems are slow, steady, and targeted. Use soaker hoses or drip systems in flower beds and around groundcovers, trees, and shrubs—they can reduce water use by 20 to 50 percent. Put turf irrigation on a separate valve that hooks up to in-ground sprinkler heads or microsprayers with flow-controlled nozzles. Pay attention to how rapidly (or sluggishly) the water is being absorbed and adjust the emission rate accordingly. Be sure to add a moisture sensor to any automated system so it doesn't go off in the rain. If yours is a manual operation, install a simple rain gauge to determine how much rainfall has reached the ground in any given area; supplement just enough to meet plants' demands.
Mulch in moderation. A 2- to 3-inch layer of aged pine bark, hardwood mulch, shredded leaves, or pine needles helps retain moisture. It also helps hide irrigation lines and suppress thirsty weeds. But don't overdo it: Too much moisture at ground level encourages roots to form close to the surface rather than down deep, where they'll help plants survive dry spells.
Establish a regular maintenance schedule. Plants that are happy and well-fed—not pruned back to sticks, beset by insects, or overcrowded—demand less water. Including, over the long haul, less toil-induced sweat off your own brow.
Similar slabs of concrete—positioned together but above turf level—form a patio.
More Tips for Reducing Water Waste
Water only in the early morning , when it's cooler and less windy, to reduce evaporation. Watering when the
sun is beating down can cause up to 90 percent of moisture to evaporate away.
Raise your lawn-mower blade to 2 1/2 to 3 inches. Allowing turf grass to grow a little taller naturally shades
its roots and helps keep the sun from drying out the soil.
- Cluster like plants with like. Not only are dramatic masses of plants more effective from a design perspective, they allow you to "hydro-zone" your yard according to moisture needs, so you aren't drowning low-water plants. Research plants' specific requirements by reading nursery tags or asking for advice at the local garden center.
Harvest rainwater runoff. Install gutter-fed rain barrels or consider an underground cistern. Talk to your plumber about the possibility of capturing "gray water" from your washing machine for landscape use.
It's estimated that recycling water in these ways can reduce consumption of fresh water by up to 80 percent.