Marilyn Hanson, Sonoran Desert Weedwackers coordinator, shows the rachis, the central stalk, of Buffelgrass (also shown below).
Buffelgrass has exploded in the Santa Catalina Mountains, and it might soon be too late to protect some of southern Arizona’s most beloved desert, a University of Arizona researcher says.
Photos of the south face of the mountain range show the African grass has swept in with a vengeance. Smaller clumps are coalescing into broad stretches of the yellowish grass, which can be seen from miles away, said Aaryn Olsson of the UA Office of Arid Lands Studies.
“I don’t think it’s too late, but I think if we don’t act aggressively and act quickly, it will be too late soon,” Olsson said.
He is asking the public to send him photos taken in the Catalinas that might show buffelgrass. Plotting the photos by date will help researchers gauge the spread of the grass, which chokes out native plants and increases wildfire risk.
Though it might seem futile, yanking out buffelgrass – which resists herbicides most of the year – can work if you catch the plants early, said Travis Huxman an assistant professor in UA’s ecology and evolutionary biology department.
The explosion in the Catalinas is not unexpected and has likely been brewing for some time. Buffelgrass spreads quickly, but the rapid growth becomes noticeable only when larger areas are involved, Huxman said.
“That’s how invasions happen, especially with this species,” he said.
Pulling the weeds by hand has worked in Organ Pipe Cactus National Monument and Saguaro National Park, and it could be effective in the Catalinas, Huxman said.
Tucson Mountain Park, where the Sonoran Desert Weedwackers has been working since 2000, has no large areas of buffelgrass, said Marilyn Hanson, the group’s volunteer coordinator.
“We don’t have that in Tucson Mountain Park because we are attacking the patches as we find them,” Hanson said.
Weedwackers have removed about 65 tons of buffelgrass and fountain grass, another non-native grass, from the park, she said.
“We have put in 7,000 volunteer hours,” she said.
Hanson is unaware of a similar effort for Coronado National Forest, but she urged foothills residents to band together to protect their homes by pulling the weeds.
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Buffelgrass (Pennisetum ciliare)
Buffelgrass is a drought-tolerant perennial grass that grows in tufts up to 4 feet tall. It grows wild in Africa, Indonesia and the Middle East, and was brought to the Southwest in the 1930s to feed grazing cattle.
The hardy grass has dense roots that can choke out native plants by sucking up water. Buffelgrass fires burn at high temperatures, which kills native plants but not the buffelgrass. It grows at elevations from sea level to about 4,200 feet.
A Soil Conservation Service project cultivated the grass in Tucson from 1938-52. Researchers planted the grass in the wild in Avra Valley as late as the early 1980s, though that planting did not survive.
By the 1990s, scientists had realized the grass was a threat to native species.
Source: Arizona-Sonora Desert Museum
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To help
• To help the Weedwackers, call Katy Goudschaal at 615-7855, Ext. 103.
• To help researchers at the University of Arizona Office of Arid Lands Studies, send your photos taken in the Tucson, Rincon or Santa Catalina mountains to Aaryn Olsson at buffeltracker@gmail.com. Include the date the photo was taken and location.
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ON THE WEB
Sonoran Desert Weedwackers: http://aznps.org/invasives/weedwackers.html
Arizona-Sonora Desert Museum buffelgrass page: www.desertmuseum.org/invaders/invaders_buffelgrass.htm