Question: Our HOA has declared war on buffelgrass: a good thing.ย But rather than remove it, they are having intense commercial spraying of glyphosate using concentrations higher than the typical herbicide available to homeowners. I cannot find information (from scientific sources such as .edu) about the immediate or long-term toxicity of the spray on cactus or our desert trees. Do you know of any research showing what it may do?
Answer:ย According to our University of Arizona Cooperative Extension Weed Specialist,ย Bill McCloskey, direct spraying of cacti with glyphosate repeatedly will probably kill most cactus species but they can withstand incidental spray contact (i.e., the whole plant is not sprayed) intermittently and can survive a single direct spraying. Generally, we recommend spraying grass-specific herbicides for grass control (e.g., fluaziflop, sethoxydim or clethodim on bermuda grass) to avoid injuring the cacti. Unfortunately, this class of herbicides doesnโt work well on buffelgrass, but maybe repeated spraying would eventually do it. Manual removal of buffelgrass would be effective in this case but understandably hard around cacti.
Peter L. Warren is the urban horticulture agent for Pima County Cooperative Extension and the University of Arizona. Questions may be emailed toย tucsongardensage@gmail.com
