Just after sunrise on the second Saturday of each month, Claudia
Bloom and 20 friends scale the slopes of Piestewa Peak in central
Phoenix - but not just for an invigorating hike or the splendid
vistas. This small army has come to wage war, wielding pickaxes and
crowbars. Their enemy? Clump after clump after clump of buffelgrass.
The weed is so invasive that it threatens the ecology of the
Sonoran Desert, choking out native plants, including the iconic
Volunteer groups like Ms. Bloom's - part of the recently formed
Phoenix Weedwackers - have dedicated thousands of hours to hacking
and prying buffelgrass out of the rock-hard Arizona earth. State
agencies are now taking up arms, too, spraying roadsides to kill it.
But buffelgrass is one tenacious species, propagating so often
that seven plants seem to spring up for every one yanked out and
packed off, ignominiously, in a 30-gallon trash bag.
"It's probably impossible to completely eradicate now," says Ed
Northam, a weed biologist and invasive-plants manager for the
University of Arizona Cooperative Extension. The best these
volunteer groups can do, he says, is develop an "approach to figure
out which areas we want to protect and start developing buffer
That's not to say no ground has been won.
Some 120 miles south of Phoenix near Tucson, the Sonoran Desert
Weedwackers for seven years have spent a morning a month clearing
buffelgrass from the slopes of the 25,000-acre Tucson Mountain Park.
Other informal groups have taken on smaller projects, as did the
volunteer squad that recently cleared the roadsides of Galvin
Parkway in Phoenix's Papago Park, home of the Desert Botanical
Garden and the Phoenix Zoo.
A native of South Africa's savannahs, buffelgrass was introduced
in the United States in the 1940s, after the hard lessons of the
Dust Bowl. It seemed to be the answer to government officials'
desperate search for a plant that would hold the soil and provide
forage for cattle.
After testing and further development in Texas, its seeds were
sold to area ranchers. Since then, it has marched across northern
Mexico and southern Arizona and is now invading the central part of
Buffelgrass thrives with very little water and germinates easily
and often, producing seed heads three or four times a year, experts
say. It began its wild trek through Arizona on the wind, taking root
on roadsides, then spreading up surrounding hillsides. It starts in
tiny low clumps and grows into larger ones that can reach three to
four feet wide.
"It competes with and eventually overtakes wildflowers," says
Raul Puente, curator of living collections at the Desert Botanical
Garden here. "Its root system is thicker and more developed than
[those of] wild plants, so it eventually chokes out all the native
Perhaps more worrisome is that buffelgrass is in cahoots with