Las Vegas Sun

August 1, 2014

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Mirage in your yard

Badly done, even a desert back yard can bleed you dry.

Yes, the water-sucking grass menace is being tamed as thrifty Las Vegans realize their yards should look more like the desert than an English garden or a tropical rainforest, but the foolish can easily plant a garden of opportunistic sponges thirstier even than the demon lawn.

Blame impatience.

Sparse, responsible desert landscaping, called xeriscaping, is not immediately impressive, says Robert Morris, a UNR-affiliated horticulturist with 22 years of experience in the valley. The plants look small. So people crowd them in, looking to fill their yard now and not thinking of the day when the mesquite and sumac will grow large and thirsty. And professionals know that the sight of runty shrubs and tiny cacti can lead to buyer's remorse.

"There's a tendency of architects and landscapers to put in too many plants because they know that desert landscaping doesn't look very good at first," Morris says, "so they reduce the number of complaints by over-planting."

Or blame size anxiety.

Does a one- or even two-story home need a Canary Island date palm thrusting 70 feet into the sky? What in the Mojave Desert suggests a 40-foot chinaberry tree? Large trees are water hogs, Morris says. A mature heritage live oak uses as much water as 1,800 square feet of low-maintenance Bermuda grass.

"What are we using this plant for?" Morris asks. "If you can't answer that question, you shouldn't plant it. Not in the desert. My pet peeve is homeowners and contractors who plant things without regard to where we live."

In a place where homes and office parks are plunked down wholesale, bad ideas in landscaping can be repeated over many acres before anyone spots the problem. Consider the fruitless mulberry tree.

During the '70s and '80s, fruitless mulberry trees and European olive trees were planted all over the valley in new developments, instant trees for instant homes.

"They're pretty trees, they're a soft wood and fast-growing," says Gary Miller of Clark County's air quality department. "They're low water users. People like trees that are fast-growing and look pretty."

They also produce pollen. A lot of it. A sinus-searing springtime load of allergens that hit so hard that the county banned the sale of the trees in 1991.

The mulberry mistake could be easily repeated, Morris says, given the tendency for whole neighborhoods to get mono-cropped with such currently trendy trees as mesquites, desert willows, acacias and chitalpas. Also a worry is Clark County's list of recommended plants, the guiding document for developers in the valley, which includes 116 approved trees.

"I think it should be 400 or 500 trees," Morris says. "Insect problems, pest problems are all going to decrease with diversity, and it cuts the risk of a collapse. For instance, people are planting shoestring acacia everywhere, but if we get a winter temperature down in the teens again, they're all going to be gone."

As far as a proper desert garden, Morris says, our goal should be variety, but fewer plants. It's not enough to admit that we don't live in a land built for lawns but rather in the desert. We also have to admit which desert we live in: the Mojave.

Too much xeriscaping here is modeled on the Sonoran desert, which gets three times as much rain as we do. Mojave plant life is sparse, so in our yards there should be space between plants, more cacti and smaller trees - for a one-story house, no taller than 25 feet. Or maybe no trees at all. For energy bill-reducing shade around the south and west sides of your home, consider fences, arbors and lattice walls covered with hardy vines. Put your thirsty plants only in parts of the yard you intend to use - near doors and on porches. Plant the rest sparsely, using plants as accents to mulch or gravel.

In an ideal world, Morris says, the whole city would be designed differently, with buildings shading each other and their own courtyards, the sort of design that has developed over the centuries in the Middle East. And every home would have a set amount of water that would force homeowners to make hard choices and trade-offs.

The Southern Nevada Water Authority isn't willing to go that far, says Doug Bennett, its conservation manager. While the agency does rebate $1 per foot of lawn removed, it insists that it be replaced with landscaping and not left bare.

"We're not talking about a pile of white rocks, a wagon wheel and a cow skull," Bennett says. "It's not that we're trying to vilify the lawn. But the ornamental lawn that's there strictly for your eye to pass over, that should probably be a thing of the past."

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