PROPERTY : Back to the earth in Arizona

"This house has such a spiritual feeling," said Kirsten Ross, as she showed me around Flying Heart, her renovated adobe home in Arizona's Sonoran Desert. "The earth walls kind of enfold you and it feels so cool in the summer heat. It's so funky."

Funky, in this case, means an oldish (circa 1945), flat-roofed, single- storey house, stuffed to the carved beams with antique Apache puberty dolls and hand-painted Mexican furniture, and a walled garden oasis, sprouting orange and mesquite trees and dozens of varieties of spiny cacti. No piece of real estate in southern Arizona is truly funky, unless it comes with a mature saguaro cactus (those big chaps with the arms), a protected species peculiar to Sonoran landscapes. But if you want the spiritual, then adobe - genuine organic, sunbaked dirt - is where it's at in this part of the world.

We are in Arizona's Valley of the Sun, a Sonora desert basin, where wilderness meets sprawling Phoenix, set against a backdrop of jagged red mountains. Phoenix and its circle of rambling satellite cities - Scottsdale, Tempe, Mesa, Chandler, Paradise - is one of the fastest-growing urban regions in the US. Attracted by the climate, the sunsets, the "indoor-outdoor lifestyle" and jobs in finance and technology (this is a Silicon Valley too), nearly 500,000 people (including 10,000 from Britain) have moved into the area in the last five years. The population has almost doubled in a decade.

Many are relocating Californians, content to move inland, and risk losing their pets to Arizona's prowling suburban coyotes rather than reside on the San Andreas Fault. Thousands more are holiday-home owners and "snow birds", an American breed of migrating pensioners, most of whom seem to come from Illinois. Naturally, the real-estate market is booming.

Those parts of the Valley's parched and prickly, but achingly beautiful, desert wilderness that haven't already been tamed and manicured are gradually disappearing under golf courses, triple carports, swimming pools and unnaturally green lawns. Conserva-tionists look on in horror as thousands of acres of Sonora's uniquely flora-ed landscape are lost to conquering developers and a tidal wave of red-roofed, bright white "stick and stucco" homes. The adobe's recent rekindling is perhaps an effort to preserve what's left of nature's desert culture.

"Our Native American, Mexican and Spanish heritage shines through as the cornerstone to our homebuilding style," reads an advert in a Scottsdale property magazine, which claims there are currently 300 developers building houses in the Phoenix area. Many are offering "custom homes" that look like adobes, but the majority are "Santa Fe wannabes" - faux adobes, rendered in various shades of desert brown, dung and sunset pink - all style and no mud.

Like the genuine article, they are characterised by sensuous and organic shapes, vigas (roof timbers that protrude through exterior walls), niches and rustic chimeneas (fireplaces), but according to Connie Binns, the owner of a 1920s adobe house at the foot of Scottsdale's Camelback Mountain, there is no comparison. "The atmosphere of a real adobe is completely different from that of an ordinary home," she insists. "When I first caught sight of this house, it reached out and wrapped its arms around me."

Five years after she bought it the house won an Arizona Governor's Award for historic preservation and was featured in Southwest Passages magazine. Arizona's home-interest glossy regularly focuses on contemporary Wild West pioneers who have bought and restored neglected adobe homes and transformed them into models of Pueblo Revivalism. The adobe aesthetic has become a fashionable facet of the "southwestern style" - a blend of Native American artefacts, Spanish colonial antiques and Santa Fe "accents", sprinkled with cowboy fringes, cacti and lizard motifs.

That aside, a rarity factor adds extra cachet to adobe-ownership. Few originals survive and only a handful of architects are working with earth. "To build with adobe is to return to an ancient tradition of the Pueblo Indians," says a sales brochure produced by Arizona's earth-sculpting artist-cum-architect, William Tull, whose homes, he says, "recreate those styles whose roots are found in the natural materials and climate of the region ... they are built with what nature provided."

Until the first railroads tore through Arizona 100 years ago, most desert architecture was earth-built. Part Indo-Mexican, part Spanish-Moorish, they were stout and flat-roofed, built around courtyards. Thick walls provided a natural thermal mass which kept interiors cool even in the heat and warm on cold nights. Adobes are the most practical of desert dwellings, but to 19th-century Anglo sensibilities mud meant poverty, peasantry and inferior building.

In 1864, journalist J Ross Browne described the Hispanic-flavoured town of Tucson, 60 miles from the Mexican border, as "a city of mud boxes, dingy and dilapidated, cracked and baked into a composite of dust and filth". At the time, Tucson was the largest settlement in the state, but the early pioneers who filed into Arizona from Europe and the eastern states couldn't wait to get out of the adobe neighbourhoods.

"The adobe does not make an attractive or clean building," wrote an Arizonan newspaper editor in 1887, "and Eastern people find it somewhat repulsive in appearance ... it is hoped that all new buildings of any pretension will be built of brick and the unsightly adobe discarded." And so it was.

Thousands of mud-built villages were swept away and replaced with Victorian- style houses. Those that remained were victim of further purges in the Sixties and Seventies - this time to make way for the thrusting glass and concrete towers that have turned the centres of modern Tucson and Phoenix into carbon copies of every other downtown district in urban America. Throughout this history of destruction, however, there were always a few maverick architects who saw the sense of using local materials and labour to build traditional desert houses.

Copper mining entrepreneur James S Douglas (otherwise known as "Rawhide" Jimmy) built himself a splendid adobe house in the Arizonan town of Jerome, in 1916. It's now a State Historic Park museum - dedicated to the rise- and-fall story of Jerome and the Douglas family's Little Daisy mine. Most of the exhibits consist of turn-of-the-century portraits, lumps of mineral- streaked rock and antique tools of the mining trade, but in a corner of one glass case is an old dirt brick. Beneath it is Rawhide Jimmy's account of how a hired Mexican work-force produced 80,000 bricks, just like this one, to build the Douglas Mansion.

"These fellows mixed dirt, straw and water together by hand and dumped it into a three-brick, ladder-like frame," he wrote. "The bricks were left in the sun to dry, but they dried rather slowly, had to be turned periodically and occupied a tremendous amount of space," The mansion - one of the largest remaining historic adobe dwellings in Arizona - outlived many of the Victorian-style villas, which crumbled into a heap of rotting timbers when the decline of the copper-mining industry turned Jerome into a ghost town.

Latterly, the influence of Frank Lloyd Wright - who died in Phoenix in 1959, 20 years after establishing his commune-like desert school of architecture, Taliesin West, near Scottsdale - helped revive Arizona's traditional adobe- type buildings.

Some of his contemporaries, such as the Phoenix society architect HH Greene (who built Connie Binns' house) experimented with earth, leaving a smattering of large, rather formal Pueblo Revival properties which today fetch breathtaking sums of money. For instance, a dilapidated Thirties adobe in Scottsdale (the former home of Horace Stonehouse, owner of the San Francisco Giants baseball team) was recently put on the market for $995,000 (roughly pounds 650,000) - almost as much as a brand new, luxury, custom- built William Tull original.

"A communion between art and nature" is how Tull describes the "Adobes de la Tierra" homes he has recently created on several acres of rugged desert land near the "Taco Deco" style El Pedregal shopping mall and the Boulders Club golfing resort in Scottsdale. The latter, designed by Bob Bacon, is a quite wonderful collection of earth-coloured, Flintstones- esque buildings set in a jumble of real and imitation granite rocks. The Boulders' little "casita" lodges look at first sight convincingly like adobe, but they don't stand up to comparison with Tull's first and only Arizona development.

Priced from $1m, every Tull house is a one-off, each lavishly upgraded versions of early native adobes. They are built from dirt blocks - made in Tucson, in exactly the same manner described by Rawhide Jimmy, nearly a century ago. Windows and doors look as though they've been pressed into wet clay. And the granulated surfaces of the thick, desert-coloured, mud walls seem to have been patted into shape by hand. They have. "The beauty of adobe is in the rhythm and music of the outline," says Tull. And the technicians of his art, mostly Mexican builders and craftsmen, spend a lot of time smoothing, bevelling and moulding their adobe brickwork and rendering.

Surrounded by ironwood, prickly pear and mature saguaros, the houses feature Moorish arches, spruce and pine beams and vigas, cool tiled courtyards, indoor and outdoor chimeneas, rock-strewn "entry patios" and steps that lead up to roof terraces. Shutters and garage doors are made from saguaro ribs and many of the gates and doors are hand-forged iron or imported Mexican antiques.

One of Tull's committed buyers is English management consultant John Scott-Oldfield, who intends to flit from London flat to Scottsdale adobe as often as possible "to refresh my batteries". The initial attraction, he says, was Arizona but despite the fact that he could have bought a massive, three-and-a-half bathroom holiday home almost anywhere in the state for under pounds 200,000, he was seduced by the magic of sun-dried dirt. "Tull's houses look like beautifully sculpted mounds of earth," he says. "They seem to grow out of the desert and he thinks very carefully about how each sits on the land and where the sun is in relation to the placing of the rooms. They are expensive because they are works of art."

Tucson architect Bob Vint, another protagonist of contemporary adobe, confesses to a crisis of conscience over the hypocrisy of reproducing native mud-built homes for wealthy clients. "When I was a kid there was a huge community of traditional adobe homes in Tucson," he recalls. "People dismissed them as slums, lived in by a bunch of Mexicans who didn't know any better. And by the time they started to say, `Hey, these old houses are pretty neat, let's do something with them,' most of them were gone." What remains of Tucson's Mexican quarter now houses lawyers, doctors, artists, teachers and the like.

"Okay, so some of the original buildings have survived. We are preserving the architecture, and have even started to emulate it," says Vint. "But we are destroying the culture that created it. The families that built these homes, and lived in them for generations, have been driven out and forced into crumby flats." For those still making a living out of sun- drying bricks and sculpting spiritually native homes for the rich, that must really stick in the throat.

! For further information on William Tull's Adobes de la Tierra homes in Arizona, California and New Mexico, contact the Tull Company (00 1 602 949 0575), 5658 North Scottsdale Road, Scottsdale, Arizona 85253.

True West Tours (00 1 602 468 0077), run by Scottsdale-based Karen Olsen, specialises in desert culture, art and architecture - and can include visits to interesting private houses.

Arizona, now linked to London by direct BA flights to Phoenix, is starting to develop a British overseas market in desert holiday homes - and is generally better value than Florida. For advice about buying property in southern Arizona, contact British expat John Hacche of West USA Realty in Paradise Valley on 00 1 602 998 2592/596 8704.