To prevent the spread of buffelgrass, Saguaro National Park officials plan to treat 18 miles of roadways and 173 acres of wilderness in the Tucson and Rincon mountains with herbicides in the next three weeks.
Monsoon rains have brought the dormant weed back to life. The non-native buffelgrass competes with native plants, such as saguaros and palo verdes.
In particular, the grass carries a higher fuel load. Buffelgrass-fueled wildfires burn hotter and move faster than normal fires, according to scientists.
There are two main ways to eradicate buffelgrass. If more than half of the plant is green, herbicides can kill it. Herbicides are absorbed only by the green, living leaves. If a plant is less than half green, manual removal is the best method, though a slow, labor-intensive process.
Pulling alone cannot keep up with rapidly spreading buffelgrass.
During the treating of Saguaro National Park, a blue or red dye will be mixed with the spray to mark plants that have been treated.
Park employees will use the herbicide glyphosate, which is available under several commercial names, including Roundup. Glyphosate is a type of salt that inhibits the action of an enzyme found only in plants that is essential to their growth.
While park officials aim only to treat buffelgrass, crews also may spray other non-native species, including fountain grass and Bermuda grass.