Herbicide Applications
Herbicide applications for county natural lands or rights-of-way.
| Start | End | Location | Open to the public | Product | Notes |
|---|---|---|---|---|---|
| 2025/06/0206/02/2025 | 2025/06/0606/06/2025 | Carolyn Holmberg Preserve at Rock Creek Farm | Yes | Ecomazapyr 2SL | The Boulder County Agricultural Division will be doing a dam infrastructure protection treatment at Stearns Lake. |
| 2025/06/0406/04/2025 | 2025/06/0406/04/2025 | Heil Valley Ranch | Yes | Quinstar 4L | Spot spraying for eradication species Leafy Spurge. Application will occur during the morning and be finished before 10 am. |
| 2025/06/0206/02/2025 | 2025/06/0506/05/2025 | Mayhoffer (Superior) - Coalton and Meadowlark trails | Yes | telar, milestone, vista | Spot spraying from truck-mounted sprayer to treat curly dock, thistles, diffuse knapweed. |
| 2025/05/3005/30/2025 | 2025/05/3005/30/2025 | Boulder County Fairgrounds | Yes | Plainview SC & Quinstar 4L | Treatment of weeds around demonstration plot infrastructure and walkways. |
| 2025/05/2705/27/2025 | 2025/05/3005/30/2025 | Boulder County ROW | Yes | Milestone | Spot spraying for eradication species: Russian Knapweed |
| 2025/05/3005/30/2025 | 2025/05/3005/30/2025 | OverBrook Trail | Yes | Quinstar 4L | Spot spraying for eradication species: Leafy Spurge |
| 2025/05/1205/12/2025 | 2025/05/1505/15/2025 | Hall Ranch 2 | No | Milestone and Telar | Treating diffuse knapweed, dalmatian toadflax, houndstongue, thistles, burdock, hoary cress, flixweed, sulfur cinquefoil |
| 2025/05/1605/16/2025 | 2025/05/1605/16/2025 | Boulder County ROW | Yes | Tordon 22K | Spot spraying for eradication species: Russian Knapweed *STARTED & COMPLETED* 5/16 |
| 2025/05/1605/16/2025 | 2025/05/3005/30/2025 | Boulder County and State Highway ROW | Yes | Quinstar 4L | Spot spraying for eradication species: Leafy Spurge *STARTED* 5/16 *EXTENDED* 5/16 |
| 2025/05/0705/07/2025 | 2025/05/3005/30/2025 | Spring Valley Rd (Boulder) | Yes | Ecomazapyr | Cut stump treatment of Russian Olives on roadside for driver and road safety. *RESCHEDULED* 5/7 due to weather. *RESCHEDULED* 5/14 due to staff capacity. *RESCHEDULED* 5/22 due to staff capacity. |
| 2025/05/0505/05/2025 | 2025/06/0506/05/2025 | Monarch Park - Niwot Trails | Yes | telar, milestone, vista | Touch up spray treatment of curly dock, teasel, prickly lettuce, thistles to maintain integrity of ecological restoration project. *POSTPONED* 5/8 due to weather *STARTED* 5/14 *POSTPONED* 5/15 due to weather *POSTPONED* 5/29 due to weather |
| 2025/04/2804/28/2025 | 2025/05/0105/01/2025 | Agricultural Heritage Center HWY 66 | Yes | Ecomazapyr | Cut stump application to tree near building foundation to prevent tree/tree roots from damaging infrastructure. COMPLETED 05/01/2025 |
| 2025/04/2804/28/2025 | 2025/05/2305/23/2025 | Tommy Thompson - Rock Creek Trail | Yes | Telar and Vista | Spray treatment of curly dock, teasel, kochia, thistles, hoary cress for suppression *STARTED* 4/29 *POSTPONED* 5/8 due to weather *COMPLETED* 5/14 |
| 2025/05/2805/28/2025 | 2025/05/2305/23/2025 | Ruth Roberts - Ruth Roberts Connector Trail | Yes | Telar and Vista | Spraying treatment of curly dock, teasel, kochia, thistles, hoary cress for supression *POSTPONED* 5/1 due to staff capacity *POSTPONED* 5/8 due to weather *POSTPONED* 5/15 due to weather *CANCELED* 5/29 due to staff capacity |
| 2025/04/2104/21/2025 | 2025/04/2404/24/2025 | Monarch Park | Yes | Telar and Vista | Spraying for curly dock, teasel, musk thistle. *COMPLETED 4/23/25* |
| 2025/04/1404/14/2025 | 2025/04/1704/17/2025 | Hall Meadows | No | Transline | Application to control diffuse knapweed and increase the biodiversity of a restoration site. |
| 2025/04/1004/10/2025 | 2025/04/1004/10/2025 | Cemex Stone Canyon Property | No | Transline | Early season treatment for Diffuse Knapweed to enhance biodiversity and preserve significant natural communities. *Rescheduled from 4/8 to 4/10. *Completed on 4/10 |
| 2025/04/0704/07/2025 | 2025/04/1004/10/2025 | Golden Fredstrom (Near St. Vrain Rd and 75th St.) | No | Telar - 1.5 oz/acre, milestone - 5 oz/acre | Application to control teasel, houndstongue, Canada thistle, bull thistle, common mullein, diffuse knapweed. Completed on 4/10/2025 |
| 2025/04/0704/07/2025 | 2025/04/1104/11/2025 | Carolyn Holmberg Preserve at Rock Creek Farm | Yes | Imazpyr | Stump applications around historical buildings. *Started & Completed on 4/9/25 |
Mowing Reports
Mowing activities are recorded for Boulder County maintained roads.
| Start | End | Location | Notes |
|---|---|---|---|
| 2025/05/2805/28/2025 | 2025/05/2905/29/2025 | Boulder County Maintained Roads between Boulder and Louisville and between Erie and Lafayette | Cherryvail Rd, Marshall Rd, S 66th St., 76th St, South Boulder Rd, Dillon Rd, Jasper Rd, 119th and Arapahoe. |
| 2025/05/1905/19/2025 | 2025/05/2205/22/2025 | East Boulder County. South of HWY 52 & Niwot Rd. | |
| 2025/04/2804/28/2025 | 2025/05/0205/02/2025 | County Maintained roads North of State Highway 66 Between 75th St and East County Line Road. |
Drone Applications
You can sign up to receive email or text notifications about scheduled drone herbicide applications. Notifications will be sent out on the Friday before the week of application. Drones may be used in areas where the terrain is too steep for worker safety, tractors cannot operate safely, or the area is too large for other methods to be practical. They are also ideal for smaller, remote applications in places that are otherwise inaccessible. To ensure safety, drones are operated at least 50 feet away from property boundaries and a minimum of 660 feet (1/8 of a mile) from residential areas and municipal boundaries.
| Start | End | Location | Open to the public | Product | Notes | Map |
|---|---|---|---|---|---|---|
| 2025/05/1905/19/2025 | 2025/05/2305/23/2025 | Hall Ranch Quarry Site | No | Milestone | A drone herbicide application will be conducted during this timeframe by the managing contractors to fulfill state requirements for mine reclamation at the Hall Quarry Site before management of the site is transferred to Boulder County control. A drone application is preferred over other application methods for personnel safety and because drones operate 20 feet or less from the ground, move at slower speeds and in patterns, and can be programed to spray small, specific areas. | View Map |