News Release

Saguaro National Park to Use Ground-based Herbicides to Control Buffelgrass

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Date: August 6, 2019
Contact: Perry Grissom, 520-733-5179

Tucson, Arizona- Natural Resource crews at Saguaro National Park are set to start herbicide treatment of buffelgrass.

Now that monsoon rains have brought dormant plants back to life, staff and interns at Saguaro National Park will begin the seasonal use of herbicides to control buffelgrass. The Park has been using groundbased herbicide applications to control buffelgrass and other invasive non-native species since 2005. Many city, county, state, and federal agencies are also spraying buffelgrass at this time of year. Buffelgrass is an aggressive, non-native grass that competes with native plants such as saguaros, paloverdes, and many other native Sonoran Desert plants. Buffelgrass can also carry hot and intense fires in an ecosystem that is not adapted to fire. If buffelgrass continues to spread, it will be a serious threat to biological conservation efforts, and buffelgrass fires may also become a major threat to public safety and property.

Buffelgrass is listed as a noxious weed by the state of Arizona. There are two main ways to effectively control buffelgrass. If more than half of the plant is green, herbicides with the active ingredient glyphosate are used. This herbicide is absorbed by the green, actively growing leaves. If the grass is less than 50% green, hand 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 park land in both the Tucson Mountains and Rincon Mountains during the next 2 to 3 months beginning on August 7, weather permitting. No public closures are anticipated. Most areas are away from trails, but if spraying will be done near a trail, signs will be present to notify park visitors. An area is safe to enter as soon as the herbicide dries which is within 15 minutes after application. A blue dye will be mixed with the spray to mark plants that have been treated. Buffelgrass is the primary target, but other invasive non-native plants such as Fountain Grass, Natal Grass, and African Lovegrass will be treated opportunistically if they are encountered. In the backcountry, water containers have been distributed by mules and helicopters for use by the crew members; if found please do not disturb. Park employees and volunteers, including local residents and school groups have been instrumental in helping to manually remove buffelgrass in the park. This is done fall through the spring. Tucson Clean and Beautiful, Sonoran Desert Weed Wackers, and many other groups are working to control buffelgrass in the Tucson community.

For additional information, please visit these websites:


Last updated: August 7, 2019

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3693 S Old Spanish Trail
Tucson , AZ 85730


(520) 733-5153

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