20 the American Gardener

WITH DROUGHT affectingmany different regions of theUnited States—most notably

the Southeast—in the last decade, water-thrifty gardens have become relevant al-most everywhere. Water shortages andrationing in some areas have generatednews stories on a variety of ways garden-ers are trying to cope, ranging fromdrilling wells in order to water their gar-den, using graywater from the house-hold, and putting down artificial turf inlieu of lawns. In some regions, commu-nities are proposing or investigating leg-islation that would ease homeownerassociation and municipal restrictions onwhat gardeners can plant so that thirsty

lawns and plants can be replaced withdrought-tolerant species.As a garden designer in Arizona, I have

had to face the challenge of creating at-tractive and drought-tolerant landscapes.Few would dispute that the region I workin—which encompasses major urban areassuch as El Paso, Tucson, Phoenix, LasVegas, and Palm Springs—is the most dif-ficult and extreme area of the United Statesin which to garden. Part of this is due toextreme heat, but the bigger issue is water,or the lack thereof. We are running out ofwater in the West, and the price of this pre-cious commodity keeps rising.Given our triple-digit heat and aridity,

you might think this is a ridiculous place

to attempt a garden. But when viewedthrough perspicacious eyes, a whole newgardening paradigm presents itself. Thisnew paradigm has two main tenets: creategardens that look good and use a lot lesswater than traditional landscapes. Al-though I’m working in the driest part ofthe country, the approaches that work herecan easily be applied to wetter regions thatare now experiencing periodic—or regu-lar—droughts. In the following pages I’llshare some of my favorite strategies for de-signing water-thrifty gardens.

KILL YOUR LAWNDuring the last five years, I’ve designedmore than 100 residential gardens forclients in Arizona. Of those people, onlyone has requested a lawn. Conversely,many clients have requested turf removal.My admonition is: if the only time youstep on your grass is to mow it, remove it.The popularity of turf removal is partly theresult of rising water bills. One of myclients, when faced with a $300-a-monthwater bill, decided that her turf was nolonger a financially sustainable part of heryard. Replacing a monoculture of turf witha vibrant fabric of drought-tolerant nativeplants is the fast road to water savings inresidential gardens. Many municipalitiesin the West, including Las Vegas, have evendeveloped programs that pay homeowners(up to $1.50 per square foot) to replacetheir grass with drought-tolerant plants.Removing a swath of water-sucking

lawn also offers a huge design opportuni-ty. The removal of turf creates a blank can-vas that allows homeowners and gardendesigners to reinvent a space in three di-mensions—complete with a diverse paletteof trees, vines, and wildlife-attractingplants—rather than a flat, green plane.

ADOPT EFFICIENT IRRIGATION PRACTICESEven in desert regions, relatively ineffi-cient methods of garden irrigation are still,unfortunately, commonplace. In homelandscapes, a water-wise garden irrigatedvia drip irrigation can reduce water use byat least 75 percent when compared withturf grass watered by sprinkler systems.Drip technology pinpoints the delivery ofwater exactly to a plant’s root zone andmakes it possible to grow plants withoutflooding or sprinkling a large area. Becausedrip emitters only wet a small circumfer-

designingWater-ThriftyGardens

Using strategies learned from the Southwest, gardeners

anywhere can plan and create a beautiful landscape that requires

minimal watering.

Spacing plants widely reduces water use and enhances the plants’ sculptural qualities.

BY SCOTT CALHOUN

designingWater-ThriftyGardens

Originally published in The American Gardener, July/August 2009

ence of soil near the root zones ofdesirable plants, they also don’t en-courage weed seeds to germinate else-where in the garden.For more water-needy plants, it’s

easy to create different zones based onwater requirements. Modern drip ir-rigation systems can be programmedto deliver water more frequently inone zone of the garden than in others,to take into account these variableplanting zones.

ADAPT TO RAINFALLThe concept of rain gardens is be-coming popular in many areas, butin different regions they can haveslightly different functions. In re-gions with high annual rainfall lev-els, rain gardens function primarilyto slow down and contain runofffrom roofs and hardscapes, reducingthe flow into storm sewers and waterbodies. In drier regions of the country,they also serve to channel water into gar-den areas that can be maintained withoutregular irrigation.Although the phrase “desert rain gar-

den” might seem like an oxymoron,with careful planning such a garden canbe built. By design, the rain garden isthe most water-efficient type of gardenyou can install. Long term (because ofsalt build-up and water scarcity), rain

gardens are probably the only truly “sus-tainable” gardens that extremely dry re-gions like the Southwest will support. Adesert rain garden will be composed ofthe very toughest and most drought-tol-erant native plants and will use a highpercentage of the superstars of drought

tolerance: cacti and other succu-lents. As I discuss further in thesidebar on page 23, rain gardens canbe created by contouring the landto form depressions that will collectrainwater.Another effective method is the

use of tanks, or cisterns, that collectrainwater from your roof during wetspells and store it for use during drytimes. The technology to connectrainwater collection cisterns to drip ir-rigation systems is already at hand andI suspect that in the near future, rain-water storage tanks will be as com-mon as downspouts—especially indrought-prone regions.

EMBRACE MINIMALISMInmy region, gardens save water notonly because they use water-thriftyplants, but also because those plantsare spaced further apart than in a

traditional garden design. It may takesome getting used to, but sparse land-scapes have their own beauty that growson you over time.Minimalist gardens are characterized by

stillness and equilibrium between plantedand unplanted spaces. In minimalist desertgarden design, the placement of each plantand rock is important. Minimalist desertgardens often rely on long-lived succulentplants for structure; for this reason, theycan be more satisfying and enduring thangardens that employ a higher percentage ofshorter-lived herbaceous plants.Chinese and Japanese gardens have

long embraced the idea of negative spacebetween plants and this concept can beused even in regions where water is notas scarce as it is in the desert. Whenworking in a minimalist theme, makesure to carefully consider the top dress-ing you use—whether it is gravel, riverrock, or shredded bark—since more of itwill be visible than in intensively plantedbeds and borders.Although sculptural succulents fit well

in a minimalist planting, perennials andwoody plants can work as well. InDuchess County, New York, designerDuncan Brine uses perennials and grassesin a manner that accentuates each plant.At the back of the border, the plantings aremore dense, but as the plantings encroachon a gravel walkway, they are set apart in

21July / August 2009

In dry regions, cisterns like this one, cloaked in yellow morning glory vine or yuca vine(Merremia aurea), provide a way to capture and store rainwater for later use.

In this California garden, water-thrifty plantssuch as Mexican daisy and New Zealandflax flank a decorative dry steam bed.

22 the American Gardener

a space that is neither pathway nor plant-ing bed. The bed has a sort of New Eng-land Zen feel to it.

SUCCULENTS RULE!It almost goes without saying, but becauseit is often ignored, it bears repeating: Youcan’t design a water-thrifty garden withwater-guzzling plants. The good news isthat for nearly every thirsty exotic plant,there is usually a water-wise substitute thatwill serve the same landscape purpose.Cacti and succulents are more than

mere accent plants in the Southwest;they form the sculptural backbone ofarid gardens. Creative designers and gar-deners have created incredible showcasesfor how to use these plants, includingPeckerwood Garden in Hempstead,Texas, and the Ruth Bancroft Garden inWalnut Grove, California. Public gar-dens such as the Desert Botanical Gar-den in Phoenix, Arizona, also providegardeners with inspiration and practicaltips for planning and planting gardensusing a diverse palette of succulents.Plants such as agaves and yuccas come

in varieties that thrive in every part ofNorth America. Lest you think that this

Top: A mixture of American natives and Mediterranean plants thrive without supplementalirrigation on this rocky slope in Karen Bussolini’s Connecticut garden. Above: Succulentsand regional natives replaced lawn in this Southwest garden.

ResourcesDesigning with Succulents by DebraLee Baldwin. Timber Press, Portland,Oregon, 2007.

The Dry Garden by Beth Chatto. Sagapress, Sagaponack, New York,1996 (original edition 1978).

Dryland Gardening: Plants that Surviveand Thrive in Tough Conditions byJennifer Bennett. Firefly Books, Buffalo, New York, 2005.

Plants and Landscapes for Summer-DryClimates of the San Francisco Bay Region, Nora Harlow, editor. East BayMunicipal Utility District, Oakland,California, 2004.

The Weather-Resilient Garden byCharles W.G. Smith. Storey Publish-ing, North Adams, Massachusetts,2004.

mania for spiny plants is limited to theSouthwest, take a look at the variety ofagaves that nursery owner Tony Avent isgrowing at Plant Delights Nursery inNorth Carolina; visit Chanticleer gardenin Pennsylvania and admire the wonder-ful and strange beaked yuccas in its dis-play gardens; or stroll by ThomasHobbs’smaller scale “jewel box” garden in Van-couver, British Columbia.It is clear that these plants are im-

mensely appealing to gardeners—nomat-ter where they live—who love strongforms. In addition to their alluring forms,agaves and many other similarly rosette-shaped plants are morphologically de-signed to harvest rainfall and direct it totheir roots. In this way, each plant is like asmall water-harvesting sculpture.

BORROW THE VIEWSeeing that so many garden settings aregraced with dramatic mountain, sky, for-est, or ocean views, the Japanese designprinciple of Shakei, or “borrowed land-scape,” can often be well employed indrought-tolerant gardens.Framing and fronting a picturesque

view of mountains or wild plantings is aninexpensive way to add plants and extradimension to your garden. Panayoti Ke-laidis, senior curator and director of out-reach for Denver Botanic Gardens, saysthat this practice, which he terms “vistaand vignette,” is a hallmark of westerngardens. In other parts of the country, theview you borrow might be more aboutenclosure than horizons. But whetheryou frame a distant grove of oak trees ora neighbor’s vibrant hedge of shrub roses,it is still a way to incorporate plants thatyou don’t have to water (or prune) intoyour garden.

TARGET YOUR SHADEIn my region, cities like Las Vegas andPhoenix have become “heat islands” inwhich increased paving and develop-ment cause the mean temperature torise by as much as 10 degrees comparedwith surrounding areas. The urban heatisland effect can be found in all NorthAmerican cities, which means, morethan ever, that we need trees to castshade and serve as passive solar coolersto help reduce temperatures in ourhomes and gardens.

23July / August 2009

CONSIDER A RAIN GARDENLike the first syncopated raindrops falling on a tin roof, a new kind of gardening isdrumming up interest across the United States. This movement—sometimes re-ferred to as “rain gardening”—aims to create gardens that will absorb runoff fromroofs and hardscaping and thrive on rainwater alone. The idea is based on the phi-losophy that gardens should live within a sustainable water budget. This is general-ly defined as the amount of rain that falls on your lot over the course of a year.

MUNICIPAL APPLICATIONSDriven by the need to find alternatives to traditional (and expensive) stormwater man-agement systems, municipalities have provided much of the initial momentum in pro-moting the idea of rain gardens. For this reason, many of these water-efficient gar-dens appeared first in commercial projects. In Portland, Oregon, the New SeasonsSeven Corners Market is designed to direct rainwater runoff from the roof and pavedareas toward concave garden beds planted with horsetail reed and other plants thatwithstand both drought and deluge.

Closer to my home base, in Tucson, our city council has recently approved a mea-sure that will require all new commercial landscapes to supply half of their outdoorwatering needs throughrainwater collection. Thisprogressive movementmeans rain gardening isprobably coming to theplanting beds around theparking lot of a new gasstation or grocery store inyour neighborhood.

HOME RAIN GARDENSIn a home landscape,rain gardening can beginwith a shovel. By diggingdepressions in your gar-den to retain rainwaterthat runs off of hard sur-faces such as roofs anddriveways, you can cre-ate beautiful concavegarden areas and fillthem with free-drainingsoil mixes.

The trick to design-ing these bowl-shapedspaces is to include arange of plants suited tothe different moisture zones. Some plants will only tolerate the slightly drier mar-ginal edges of a rain garden, while others that like wet feet will thrive despite oc-casional submersion at the bottom of the basin. As a starting point, consider thesmall sampling of American natives (linked to this article on the AHS website)that are appropriate for rain gardens in many areas of the country. Supplement orreplace these with plants native to your region; in many municipalities, water com-panies, departments of environmental resources, or similar agencies offer guide-lines and plant lists for creating rain gardens. —S.C.

A gravel basin collects precious rainwater and steers it tosedges, rushes, and other plants on its perimeter.

Trees can greatly ameliorate the effectof urban heat islands. In our home gar-dens, we can actually grow our own “airconditioning” by planting trees aroundour homes. Even though shade trees usu-ally require more water to establish thansmaller plants, the expenditure is worth it.Then, youmight ask, “Howdoes plantingtrees save water?” Because most powerplants use large quantities of water to pro-duce electricity, by reducing your need forair conditioning, you are saving bothwater and energy.

CREATE STUNNING BEAUTYWhen the concept of drought-tolerantgardens started coming into vogue somethree decades ago, the term “xeriscape”was coined to describe the idea. Becausesome of these early gardens were ratherdrab and unimaginative, critics calledthem “zeroscapes” and the concept re-ceived much negative publicity.

The diversity of plants suitable forwater-thrifty gardens has evolvedtremendously in the intervening years,but aesthetics might still be the most ne-glected aspect of drought-tolerant gardendesign. Certainly our native plants andsome well-adapted exotics from Mediter-ranean regions are every bit as beautifulas many of the thirsty non-natives thathave become standard in our landscapes,but we need to arrange them in a waythat shows off their best characteristics. To put it another way, if we are going

to encourage other gardeners to tear outor reduce their lawns and standard bor-der plantings, the replacement gardenhad better be dynamic, colorful, grace-ful, and well balanced. Just because agarden is drought-tolerant doesn’t meanthat it is exempt from commonsense de-sign principles. �

Garden designer and award-winning au-thor Scott Calhoun lives in Tucson, Arizona.His most recent book, The Hot Garden, hasjust been released by Rio Nuevo Publishers.

24 the American Gardener

Left: Indian blanket, shrubby cinquefoil, and‘Mainacht’ salvia carpet the ground in thisdrought-tolerant garden in centralWashington. Bottom left: In the West, low-water gardens benefit from “borrowing” theview of the surrounding natural landscape.