Sue Rutman had been warned: Buffelgrass, she'd been told, loved disturbance. Pulling up the weed would only overturn more desert soil, spread seeds, and encourage its expansion. But as the Organ Pipe Cactus National Monument botanist watched buffelgrass cover longer and longer stretches of park roadside, she decided to test the conventional wisdom.

"I thought, 'Well, if I let this go, I know it's going to be much, much worse. I don't know what's going to happen if I try,'" she remembers. "So I tried."

In 1995, Rutman and a group of college students cleared buffelgrass from one square mile of the monument in two days. It was tough, exhausting work: Though desert soils are usually shallow, buffelgrass roots are stubborn, and the plants themselves are heavy and unwieldy. "The place looked like it was nuked when we left," says Rutman. "There wasn't a shovelful of soil left unturned."

But the next year, buffelgrass didn't come back as expected. In fact, it hardly came back at all. "I said, 'Maybe this is doable,' " says Rutman. "So I just kept plodding along and working at it, and after a while, I realized it was working."

Rutman and her volunteers moved outward from a single spot in the desert, repeatedly searching previously cleared areas for new sprigs of buffelgrass. After five years, they'd covered 20 square miles of the park. "There are some places where we pulled out an entire field of buffelgrass - 90 huge garbage bags full of it - and there have only been one or two plants there since," she says.

Why, exactly, pulling works is something of a mystery. Less mysterious is why volunteers keep coming back to labor in the desert. "It feels great," says Rutman. "You pull these things out of the ground, and they make this wonderful rip - it's like, 'Die! Die!'"

When word of the work in Organ Pipe reached Tucson, volunteers at the Arizona-Sonora Desert Museum launched a similar effort in Tucson Mountain Park, a 20,000-acre county park on the western side of the city. Marilyn Hanson, a retired biology teacher and a leader of the Sonoran Desert Weedwackers, reports that since 2000, the group has pulled 50 tons of buffelgrass.

Every other Wednesday and every third Saturday throughout the year, the Weedwackers, now affiliated with the Arizona Native Plant Society and Pima County, spend the morning pulling buffelgrass from park grounds. Armed with 14-pound digging bars, garbage bags, and watermelon for sustenance, the volunteers pry buffelgrass and its relative, fountaingrass, out of narrow washes and rocky, cactus-studded mountain slopes. They then ferry 30- to 50-pound bags of grass to the road, sometimes a half-mile hike away.

"When you get 60 bags and pile them up, it's so concrete," says Hanson. "I think that's what drives me, and a lot of other people. It's very obvious what we've done. It's not like writing letters to Congress."

The Weedwackers, who have about eight regular members and several dozen sporadic pullers, have been joined by Rotary clubs, Boy Scout groups, homeowner's associations, and busloads of students from college fraternities. "It's a good way to work off a Saturday morning hangover," laughs Tucson Mountain Park staffer Doug Siegel. Some of these groups, in turn, have started buffelgrass- pulling efforts in their own neighborhoods, and an independent Weedwacker group now tears up weeds in Phoenix.



Despite its visible rewards in particular areas, hand-to-hand combat is slow and often costly, especially when the invasion is advanced. Though researchers spotted buffelgrass in the backcountry of Saguaro National Park in the mid-1990s, the park didn't begin consistent efforts to pull it until 2000. Staff and volunteers could only pull 30 to 55 acres each year, an effort quickly overwhelmed: By 2002, buffelgrass had infested 170 acres of the park, while its relative, fountaingrass, had invaded more than 100. "We hand-pulled for four years, until I said, 'Enough is enough,' " says Danielle Foster, a former restoration ecologist for the park. "We just weren't getting anywhere."

So the park switched to harder stuff. U.S. Geological Survey ecologist Todd Esque, who studied buffelgrass and fire at the park for about a decade, found that without the help of volunteers, hand-pulling one acre of buffelgrass can cost more than $13,000. Selective spraying of buffelgrass with Roundup is just about as effective and can cost less than $1,000. Parks, as a rule, use herbicides in wilderness and backcountry areas only as a last resort. But in 2005, the park superintendent and regional staff approved their use for buffelgrass control.

"Once chemical control became an option, we were covering hundreds of acres," says Dana Backer, who worked on buffelgrass control at the park in 2005 and 2006. But by 2006, just as heavy rains were giving the buffelgrass an extra boost, key staff had departed, and the park had largely suspended its control efforts, relying on sporadic volunteer projects and visits from a Park Service invasive species team based in Nevada. Organized spraying efforts resumed this month.

The disadvantage of herbicides - aside from the possible secondary effects of widespread use - is that they're only effective on buffelgrass when it greens up in the summer. Pulling, on the other hand, can continue through the cooler days of the fall and winter, when volunteer work is most attractive.

In Organ Pipe Cactus National Monument, whose southern edge abuts the border with Mexico, summertime herbicide use has acquired an unexpected appeal. Because of drug-related violence along the border, the park has effectively shut volunteers - and the general public - out of backcountry areas until further notice. Since summer is the low season for drug smuggling, staffers with backpack sprayers could replace wintertime volunteers and their digging bars. "Border issues take their own direction," says Rutman, "and we respond."