Urgent Action Alert: Prevent Indaziflam drone sprays uphill from local regenerative farms

December 2, 2025

Boulder County announced in a press release on November 21st that they plan to use drones to spray both Indaziflam (brand name Rejuvra) to kill invasive annual grasses throughout the Red Hill Open Space area—which is uphill and immediately adjacent to both Yellow Barn Farm and Drylands Agroecology Research’s (DAR) Elk Run Farm—starting as soon as this week. These farms have both been outstanding leaders in healing our County’s soil for many years.  

Applications of Indaziflam this month are also planned for Heil Valley Ranch, Hall Ranch, Indian Mesa, Rabbit Mountain, and elsewhere, according to the County’s website. 

We stand in solidarity with the farmers, residents, and more-than-human relations of Red Hill—and everyone downhill and downwind—from each of these proposed herbicide applications and demand that the County stop this action and all other applications of Indaziflam unless and until there is a comprehensive, independent, long-term study on the non-target and long-term environmental and health impacts of this chemical. 

Approval by the EPA—which does not study long-term or non-target impacts before sending new pesticides to market—is an utterly insufficient standard for a chemical who’s claim to fame is its persistence in the soil and its ability to kill all seeds for years to come after just one application. Indaziflam is not approved for us in the City of Boulder, and there are other options for controlling annual grasses. 

What we don’t know about Indaziflam is truly terrifying, but what we do know is that it sterilizes soil for years. It kills ALL seeds, including natives, before they can germinate, not just the “bad ones”, leaving bare soil that in our valley will blow away with the next windstorm (carrying those chemicals that have “bonded” to the soil to spread their poison elsewhere). 

Proponents of Indaziflam point to rebounding native perennials after applications, which is a misleading marker, since those same native plans also need to produce viable seed to thrive over the long term, and especially to recover after fire. 

Time is of the essence, so please take action today to stop this.

Email Action: 

Write to the Commissioners TODAY. Clicking the link in DAR’s email helps us track how many people are writing to the Commissioners about this issue. 

In Person or Virtual Action: 

There is a County Commissioners meeting schedule set for 9am on Thursday , December 4th (this week!) Please call in virtually or attend in person to share your voice to protect our farms.

Our Demands:

1. Immediate moratorium on drone-based indaziflam applications

2. Independent scientific review of soil persistence and ecosystem impacts

3. The development of a County-specific, community-transparent chemical review process that does not rely on the now largely dismantled EPA oversight

4. Full disclosure of Bayer’s involvement in county weed management decisions

5. Public process before any broad-scale herbicide deployment

6. Investment in integrated, regenerative weed management alternatives

More Information:

• Sign Up for Alerts from the County on Planned Drone Herbicide Applications: https://content.govdelivery.com/accounts/COBOULDER/bulletins/3fc5f56

• Track the County’s Public Herbicide Applications Dataset & Planned Applications: https://bouldercounty.gov/open-space/management/weeds/#herbicide-applications

• DAR's Community Action PDF

• PEER Factsheet on Indaziflam

• View DAR's Email for More Resources and Ways to Take Action

Our soil is not a testing ground for new pesticides, and our fire-scarred lands deserve the chance to heal without chemicals.

Thank you for taking action today!