Despite the press of local publicity and the well-established risks to safety, economy, and ecology, sustained commitment and funding for buffelgrass control is difficult to secure. With the weed racing into the desert - in some places, its reach is estimated to be doubling, sometimes tripling, each year - even Betancourt admits he finds it hard to be optimistic. "I'm skeptical that we can do anything about it," he says. "It's already far along, and it's moving very quickly. But we can't throw up our hands and say it's a done deal."

The best hope, perhaps, is that the Herculean efforts in Tucson will create more than a spasm of concern about one species, encouraging governments at all levels to get more serious and more strategic about weeds. Buffelgrass or its close relatives have already invaded many places around the world, including Hawaii, Australia, and South America, even reaching the Galapagos Islands. And buffelgrass isn't the first, or the last, exotic species to threaten entire ecosystems. As species invasions - encouraged by human travel, global trade and climate change - keep rising in number and severity, governments will increasingly be forced to choose from the worst of multiple threats.

"Every area of the state has a pressing problem," says Lori Faeth, environmental advisor to Arizona Gov. Janet Napolitano, D. Earlier this year, in response to the discovery of invasive quagga mussels in the Colorado River, the governor revived a statewide invasive species council. The group is devising a management plan for combating, containing and preventing invasions throughout the state, but won't complete it until mid-2008.

The National Invasive Species Council, an advisory group created by President Clinton in 1999, coordinates the federal response, but council executive director Lori Williams says much of the responsibility for dealing with particular species lies with state and local governments. "Invasive species are inherently hard to prioritize at a national level," she says, because they can pose very different threats in different places. The council does have a list of a half-dozen uber-invaders - such as tamarisk, the brown tree snake and Asian carp - that are considered national priorities, and Williams says buffelgrass may join that list. Because of the upwelling of local and state concern, she adds, "it's a good time for us to get involved and show support."

But not every superweed has a foe like Betancourt, and the next buffelgrass may already be making its way, largely unheralded, across the desert. Few, if any, scientists question the transformative power of buffelgrass, but some say Sahara mustard, another fire-carrying invasive weed, poses an even more serious threat, because of its ability to invade a wider range of habitats. All agree that more exotics are on the way.

"We're going to get hit with a big wave of Australian things," predicts Organ Pipe botanist Sue Rutman. Australia already has serious problems with North American species such as mesquite and willow, she says, and the United States is ripe for a reverse invasion. Rutman remembers driving by a plant nursery on I-10 that advertised landscaping plants from Down Under. "They had this big sign up saying, 'Australian plants! No worries!' " she says. "And I'm thinking, 'Yes! Big worries!' "

"We've got all these other species in the pipeline, and we're going to have to deal with those, too," says buffelgrass coordinator Travis Bean. "The desert is no longer maintenance-free."

The Sonoran Desert still suffers from good intentions. Though buffelgrass is barred from Arizona's doorstep, fountaingrass, a close relative, remains a popular landscaping plant. Despite widespread warnings about the invasive nature of fountaingrass, it sits prettily on the shelves of Tucson's Home Depots, one man's weed posing as another man's decor.

Or pasture, as the case may be. To the horror of many in Tucson, state and federal agricultural agencies in Texas released a cold-tolerant variety of buffelgrass in early 1999. The grass strain, known as Frio, was a long-awaited boon for south Texas ranchers, who wanted a hardier grass that could survive winter storms. But for many southern Arizonans, a turbocharged version of the species was a nightmare come true. After complaints from scientists in Tucson, the federal Agricultural Research Service suspended its research on the "improvement" of buffelgrass.

"At that time, I didn't even know it was a problem in Arizona," says Byron Burson, whose lab selected the cold-tolerant strain from plants collected in South Africa. Frio has never been widely sold in Texas, but researchers report planting it in northern Mexico. How far it will spread remains unknown.

In 2000, alerted by Tucson scientists, members of the National Invasive Species Council met with the Agricultural Research Service about the development of the Frio strain. The council is now creating National Environmental Policy Act guidelines that would require federal agencies to consider invasive species issues. But for the moment, vigilant ecologists are the only barriers to another Frio.

When it comes to weeds, Burson points out, there's a deeper ambivalence yet to resolve. "If you don't have a grass with some invasiveness and some aggressiveness, you might as well not release it as a pasture grass, because it's not going to survive under grazing," he says. "We're trying to meet two groups' interests here. The ranchers want something that's aggressive, and the environmentalists don't want anything that's introduced."

Can he foresee any solution to that dilemma?

"Yeah," he says. "Retirement."

Michelle Nijhuis is a contributing editor of High Country News.


The Weed-wackers

Botanist Sue Rutman has had surprising success just yanking up buffelgrass, but herbicides remain the first line of defense