Now that monsoon rains have brought dormant plants back to life, staff at Saguaro National Park will again be using herbicides to control buffelgrass. Other city, county, state, and federal agencies are spraying buffelgrass at this time of year as well.

Buffelgrass is an aggressive, non-native grass that competes with native plants such as saguaros and palo verdes, and also carries wildfires that can harm these Sonoran Desert natives.  If buffelgrass continues to spread, it will be a serious threat to biological conservation efforts in the area, and buffelgrass fires may also become a major threat to public safety and property. Buffelgrass is classified as a noxious weed by the state of Arizona.

There are two main ways to eradicate buffelgrass. If more than half of the plant is green, herbicides can be used to kill the plant. Herbicide is absorbed only by the green, living leaves. If it is less than half green, manual removal is the best method. However, this is a slow, labor-intensive process, and pulling alone cannot keep up with rapidly spreading buffelgrass. 

The park plans to treat 50 miles of roadway and approximately 450 acres of wilderness in both the Tucson Mountains and Rincon Mountains during the next 3 months. No public closures are anticipated. An area is safe to enter as soon as the herbicide dries. A blue dye will be mixed with the spray to mark plants that have been treated. In the backcountry, water containers have been distributed by mules and helicopters for use by spray crews; if found please do not disturb. 

Park employees will be using the herbicide glyphosate, which is available under several commercial names, including Roundup®, Rodeo®, and Touchdown®. Glyphosate is a type of salt that inhibits the action of an enzyme found only in plants that is essential to plant growth. Most plants are susceptible to glyphosate, so it must be administered carefully to spray only species intended for control. Buffelgrass is the main target, but other non-native species will be treated opportunistically if they are encountered, including fountaingrass and Bermudagrass.  

Park employees and volunteers, including local residents and groups such as the Girl Scouts, Boys and Girls Clubs of Tucson and employees of Citigroup, also help pull buffelgrass when it is dormant and not susceptible to herbicide. 

Contact:   Dana Backer, 520-733-5179