20 Using strategies learned from the Southwest, gardeners Southwest, the from learned strategies Using Originally published in anywhere can plan and create a beautiful landscape that requires association and municipal restrictions on den, using gray using den, drilling wells in order to water their gar- h what gardeners can plant so that thirsty that so plant can gardeners what homeowner ease would that islation nities are proposing or investigating leg- commu- regions, Insome lawns. of lieu most everywhere. Water shortages and shortages Water everywhere. most thrifty gardens have become relevant al- the Southeast—in the last decade, water- r ae rig o oe rnig from ranging cope, to trying are ers news stories on a variety of ways garden- generated have areas some in rationing minimal watering. W pcn lnswdl eue ae s n nacstepat’supua qualities. sculptural plants’ the enhances and use water reduces widely plants Spacing old, and putting down artificial turf in Water-Thrifty designing Gardens Water-Thrifty designing Gardens the American Gardener American the United States—most notably many different regions of the T DROUGHT ITH water from the house- the from water The American Gardener, affecting extreme heat, but the bigger issue is water, or the lack thereof. We are running out of you might think this is a ridiculous place lawns and plants can be replaced with replaced be can plants and lawns cious commodity keeps rising. water in the West, and the price in which to garden. Part of this is due to Few would dispute that the region I work t drought-tolerant species. Vegas, and Palm Springs—is the most dif- in—which encompasses major urban areas ficult and extreme area of the United States such as El Paso, Tucson, Phoenix, Las Phoenix, Tucson, Paso, El as such had to face the challenge of creating at- creating of challenge the face to had ractive and drought-tolerant landscapes. Given our triple-digit heat and aridity, As a garden designer in Arizona, I have July/August 2009 BY SCOTT CALHOUN of this pre- though I’m working in the driest part of clients, when faced with a $300-a-month ae ta taiinl adcps Al- landscapes. traditional than water r longer a financially sustainable part of her the yard. Replacing a monoculture of turf with signing water-thrifty gardens. a vibrant fabric of drought-tolerant nati water bill, decided that her turf was no was turf her that decided bill, water lar—droughts. In the following pages I’ll new paradigm has two main tenets: create share some of my favorite strategies for de- gardens that look good and use a lot less flooding or sprinkling a large area. Because The popularity of turf removal is partlystep on yourthe grass is to mow it, remove it. Drip technology pinpoints the delivery of let nAioa ftoepol,only people, those Of Arizona. in clients can easily be applied to wetter regions that are now experiencing periodic—or regu- gardening paradigm presents itself. This through perspicacious eyes, a whole new viewed when But garden. a attempt to oeta 0 eieta adn for gardens residential 100 than more makesit possible to grow plants without My admonition is: if the only time you time only the if is: My admonition water exactly to a plant’s root zone and zone plant’s a root to exactly water systems. sprinkler by turf watered grass designers to reinvent a space in three di- plants is the fast road to water savings in uigtels ieyas ’edesigned I’ve years, five last the During LAWN YOUR KILL vni eetrgos eaieyineffi- relatively regions, desert in Even PRACTICES IRRIGATION EFFICIENT ADOPT drip emitters only wet a small circumfer- many client one has requested a lawn. Conversely, lawn. a requested has one vas that allows homeowners and gard and homeowners allows vas that in the West, including Las Vegas, have even plants—rather than a flat, green plane. developed programs that pay homeowners residential gardens. Many municipalities cient methods of garden irrigation are still, f tr of mensions—complete with a diverse palette their grass with drought-tolerant plants. lawn also offers a huge design opportuni- via drip irrigation can reduce water use by ty. The removal of turf creates a blank can- landscapes,a water-wise garden irrigated unfortunately, commonplace. In home In commonplace. unfortunately, (up to $1.50 per squar per $1.50 to (up at esult of rising water bills. One of my of One bills. water rising of esult least 75 percent when compared with compared when percent 75 least country, the approaches that work here Removing a swath of water-sucking of swath a Removing e, ie, n wildlife-attracting and vines, ees, s have requested turf removal. e foot) to replace to foot) e en ve
ence of soil near the root zones of tolerance: cacti and other succu- desirable plants, they also don’t en- lents. As I discuss further in the courage weed seeds to germinate else- sidebar on page 23, rain gardens can where in the garden. be created by contouring the land For more water-needy plants, it’s to form depressions that will collect easy to create different zones based on rainwater. water requirements. Modern drip ir- Another effective method is the rigation systems can be programmed use of tanks, or cisterns, that collect to deliver water more frequently in rainwater from your roof during wet one zone of the garden than in others, spells and store it for use during dry to take into account these variable times. The technology to connect planting zones. rainwater collection cisterns to drip ir- rigation systems is already at hand and ADAPT TO RAINFALL I suspect that in the near future, rain- The concept of rain gardens is be- water storage tanks will be as com- coming popular in many areas, but mon as downspouts—especially in in different regions they can have drought-prone regions. slightly different functions. In re- gions with high annual rainfall lev- EMBRACEMINIMALISM els, rain gardens function primarily In my region, gardens save water not to slow down and contain runoff only because they use water-thrifty from roofs and hardscapes, reducing plants, but also beca use those plants the flow into storm sewers and water are spaced further apart than in a bodies. In drier regions of the country, In this California garden, water-thrifty plants traditional garden design. It may take they also serve to channel water into gar- such as Mexican daisy and New Zealand some getting used to, but sparse land- den areas that can be maintained without flax flank a decorative dry steam bed. scapes have their own beauty that grows regular irrigation. on you over time. Although the phrase “desert rain gar- gardens are probably the only truly “sus- Minimalist gardens are characterized by den” might seem like an oxymoron, tainable” gardens that extremely dry re- stillness and equilibrium between planted with careful planning such a garden can gions like the Southwest will support. A and unplanted spaces. In minimalist desert be built. By design, the rain garden is desert rain garden will be composed of garden design, the placement of each plant the most water-efficient type of garden the very toughest and most drought-tol- and rock is important. Minimalist desert you can install. Long term (because of erant native plants and will use a high gardens often rely on long-lived succulent salt build-up and water scarcity), rain percentage of the superstars of drought plants for structure; for this reason, they can be more satisfying and enduring than gardens that employ a higher percentage of shorter-lived herbaceous plants. Chinese and Japanese gardens have long embraced the idea of negative space between plants and this concept can be used even in regions where water is not as scarce as it is in the desert. When working in a minimalist theme, make sure to carefully consider the top dress- ing you use—whether it is gravel, river rock, or shredded bark—since more of it will be visible than in intensively planted beds and borders. Although sculptural succulents fit well in a minimalist planting, perennials and woody plants can work as well. In Duchess County, New York, designer Duncan Brine uses perennials and grasses in a manner that accentuates each plant. At the back of the border, the plantings are In dry regions, cisterns like this one, cloaked in yellow morning glory vine or yuca vine more dense, but as the plantings encroach
(Merremia aurea), provide a way to capture and store rainwater for later use. on a gravel walkway, they are set apart in
July / August 2009 21 22 Walnut Grove, California. Public gar- Public California. Grove, Walnut Texas, and the Ruth Bancroft Garden in dens such dens ekrod adn n Hempstead, in Garden Peckerwood for how to use these plants, including plants, these use to how for deners have created incredible showcases a tips for planning and planting gardens planting and planning for tips g will serve the same landscape purpose. using a diverse palette of succulents. they form the sculptural backbone of backbone sculptural the form they there is usually a wate in varieties that thrive in every part of part every in thrive that varieties in tams oswtotsyn,btbecause but saying, without goes almost It RULE! SUCCULENTS plant- nor pathway neither is that space a North America. Lest you think that this den in Phoenix, Arizona, also provide also Arizona, Phoenix, in den thatfor nearly every thirsty exotic plant, it is often ignored, it bears repeating: ing bed. The bed has a sort of New Eng- mere accent plants in the Southwest; the in plants accent mere water-guzzling plants. water-guzzling land Zen feel to it. can’t design a water-thrifty garden with garden water-thrifty a design can’t rid gardens. Creative designers and gar- ardeners with inspiration and practical and inspiration ardenerswith Dryland Gardening: Plants that Survive and Thrive in Tough Conditions 1996 (original edition 1978). Jennifer Bennett. Firefly Books, Region, Sagapress, Sagaponack, New York, Climates of the San Francisco Bay Buffalo, New York, 2005. The Weather-Resilient Garden Plants and Landscapes for Summer-Dry The Dry Garden Charles W.G. Smith. Storey Publish- California, 2004. rgn 2007.Oregon, ing, North Adams, Massachusetts, Portland, Press, Timber Baldwin. Lee Municipal Utility District, Oakland, einn ihSucculentsDesigning with Resources 2004. Plants such as agaves and yuccas come Cacti and succulents are more than more are succulents and Cacti the American Gardener American the Nora Harlow, editor. as the Desert Botanical Gar- Botanical Desert the as by Beth Chatto. r-wise substitute that The good news is news good The yDebra by East Bay by by You o:Amxueo mrcnntvsadMdtraenpat hiewtotsupplemental without thrive plants Mediterranean and natives American of mixture A Top: irrigation on this rocky slope in Karen Bussolini’s Connecticut garden. Above: Succulents and regional natives replaced lawn in this Southwest garden. Southwest in this lawn replaced natives regional and
mania for spiny plants is limited to the Southwest, take a look at the variety of agaves that nursery owner Tony Avent is CONSIDER A RAIN GARDEN growing at Plant Delights Nursery in Like the first syncopated raindrops falling on a tin roof, a new kind of gardening is North Carolina; visit Chanticleer garden drumming up interest across the United States. This movement—sometimes re- in Pennsylvania and admire the wonder- ferred to as “rain gardening”—aims to create gardens that will absorb runoff from ful and strange beaked yuccas in its dis- roofs and hardscaping and thrive on rainwater alone. The idea is based on the phi- play gardens; or stroll by Thomas Hobbs’ losophy that gardens should live within a sustainable water budget. This is general- smaller scale “jewel box” garden in Van- ly defined as the amount of rain that falls on your lot over the course of a year. couver, British Columbia. It is clear that these plants are im- MUNICIPAL APPLICATIONS mensely appealing to gardeners—no mat- Driven by the need to find alternatives to traditional (and expensive) stormwater man- ter where they live—who love strong agement systems, municipalities have provided much of the initial momentum in pro- forms. In addition to their alluring forms, moting the idea of rain gardens. For this reason, many of these water-efficient gar- agaves and many other similarly rosette- dens appeared first in commercial projects. In Portland, Oregon, the New Seasons shaped plants are morphologically de- Seven Corners Market is designed to direct rainwater runoff from the roof and paved signed to harvest rainfall and direct it to areas toward concave garden beds planted with horsetail reed and other plants that their roots. In this way, each plant is like a withstand both drought and deluge. small water-harvesting sculpture. 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 outdoor BORROW THE VIEW watering needs through Seeing that so many garden settings are rainwater collection. This graced with dramatic mountain, sky, for- progressive movement est, or ocean views, the Japanese design means rain gardening is principle of Shakei, or “borrowed land- probably coming to the scape,” can often be well employed in planting beds around the drought-tolerant gardens. parking lot of a new gas Framing and fronting a picturesque station or grocery store in view of mountains or wild plantings is an your neighborhood. inexpensive way to add plants and extra dimension to your garden. Panayoti Ke- HOME RAIN GARDENS laidis, senior curator and director of out- In a home landscape, reach for Denver Botanic Gardens, says rain gardening can begin that this practice, which he terms “vista with a shovel. By digging and vignette,” is a hallmark of western depressions in your gar- gardens. In other parts of the country, the den to retain rainwater view you borrow might be more about that runs off of hard sur- enclosure than horizons. But whether faces such as roofs and you frame a distant grove of oak trees or driveways, you can cre- a neighbor’s vibrant hedge of shrub roses, ate beautiful concave it is still a way to incorporate plants that garden areas and fill you don’t have to water (or prune) into them with free-draining your garden. soil mixes. The trick to design- TARGET YOUR SHADE ing these bowl-shaped A gravel basin collects precious rainwater and steers it to In my region, cities like Las Vegas and spaces is to include a sedges, rushes, and other plants on its perimeter. Phoenix have become “heat islands” in range of plants suited to which increased paving and develop- the different moisture zones. Some plants will only tolerate the slightly drier mar- ment cause the mean temperature to ginal edges of a rain garden, while others that like wet feet will thrive despite oc- rise by as much as 10 degrees compared casional submersion at the bottom of the basin. As a starting point, consider the with surrounding areas. The urban heat small sampling of American natives (linked to this article on the AHS website) island effect can be found in all North that are appropriate for rain gardens in many areas of the country. Supplement or American cities, which means, more replace these with plants native to your region; in many municipalities, water com- than ever, that we need trees to cast panies, departments of environmental resources, or similar agencies offer guide- shade and serve as passive solar coolers lines and plant lists for creating rain gardens. —S.C.
to help reduce temperatures in our
homes and gardens.
July / August 2009 23 Trees can greatly ameliorate the effect of urban heat islands. In our home gar- dens, we can actually grow our own “air conditioning” by planting trees around our homes. Even though shade trees usu- ally require more water to establish than smaller plants, the expenditure is worth it. Then, you might ask, “How does planting trees save water?” Because most power plants use large quantities of water to pro- duce electricity, by reducing your need for air conditioning, you are saving both water and energy. CREATE STUNNING BEAUTY When the concept of drought-tolerant gardens started coming into vogue some three decades ago, the term “xeriscape” was coined to describe the idea. Because some of these early gardens were rather drab and unimaginative, critics called them “zeroscapes” and the concept re- ceived much negative publicity.
Left: Indian blanket, shrubby cinquefoil, and ‘Mainacht’ salvia carpet the ground in this drought-tolerant garden in central Washington. Bottom left: In the West, low- water gardens benefit from “borrowing” the view of the surrounding natural landscape.
The diversity of plants suitable for water-thrifty gardens has evolved tremendously in the intervening years, but aesthetics might still be the most ne- glected aspect of drought-tolerant garden design. Certainly our native plants and some well-adapted exotics from Mediter- ranean regions are every bit as beautiful as many of the thirsty non-natives that have become standard in our landscapes, but we need to arrange them in a way that shows off their best characteristics. To put it another way, if we are going to encourage other gardeners to tear out or reduce their lawns and standard bor- der plantings, the replacement garden had better be dynamic, colorful, grace- ful, and well balanced. Just because a garden is drought-tolerant doesn’t mean that 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, has
just been released by Rio Nuevo Publishers.
24 the American Gardener