July 6, 2009
Contact: Dana Backer, 520-733-5179
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 effectively eradicate buffelgrass. If more than half of the plant is green, herbicides can be used. The herbicide currently used by the park is absorbed only by green, actively growing leaves. If the grass is less than 50% 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 approximately 50 miles of roadway and 450 acres of wilderness in both the Tucson Mountains and Rincon Mountains during the next 3 months, beginning in mid-July. No public closures are anticipated. An area is safe to enter as soon as the herbicide dries, which takes about 30 minutes. 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 an herbicide with the active ingredient glyphosate, which is available under several brand names, including Roundup®, Rodeo®, and Touchdown®. Glyphosate inhibits the action of an enzyme found only in plants that is essential to plant growth. Glyphosate is non-selective, so it needs to be administered carefully to spray only species intended for control. Buffelgrass is the primary target, but other non-native grasses such as fountain grass, natal grass, African lovegrasses, and Bermuda grass will be treated opportunistically if they are encountered.
Park employees and volunteers, including local residents and groups such as Eagle Scouts, high school and college clubs, and employees from Citigroup and TEP have been instrumental in helping manually remove buffelgrass in the park.
For additional information, including a map of areas to be treated, please visit these websites: