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Herbicide Application & Roadside Mowing
2025 Reporting System

Herbicide Applications

Herbicide applications for county natural lands or rights-of-way.

Start End Location Open to the public Product Notes
2025/08/1108/11/20252025/08/1408/14/2025Lagerman Agricultural Preserve - Open Sky Loop from Link trail East to 75th st.YesMilestone, Telar XPSpot spraying for listed weed species canada thistle, musk thistle, scotch thistle, common teasel, common mullein, chicory, dalmatian toadflax.
2025/08/1108/11/20252025/08/1508/15/2025Betasso Preserve Open Space - Canyon Loop trail, Betasso Link trail, Blanchard trailYesMilestone, Telar XPSpot spraying for listed weed species canada thistle, musk thistle, common mullein, st. johnswort, poison hemlock, diffuse knapweed.
2025/08/1108/11/20252025/08/1408/14/2025PrescottNoMilestoneTreatment of Canada thistle in fen restoration area.
2025/08/1908/19/20252025/08/1908/19/2025Nederland Sort Yard and Transfer Station YesMilestone, Telar XPSpot spraying for eradication species oxeye daisy and scentless chamomile
2025/08/1808/18/20252025/08/2908/29/2025CR 126, CR 128, Ridge Rd., YesMilestone, Telar XPSpot spraying for eradication species oxeye daisy, yellow toadflax, scentless chamomile
2025/08/1808/18/20252025/08/2908/29/2025Mud Lake -Caribou Ranch Link, Kinnickinnick Loop, Tungsten Loop, Chickadee Trail, Sherwood Forest TrailYesMilestone, Telar XPSpot spraying for listed noxious weed species
2025/08/1808/18/20252025/08/2908/29/2025Caribou Ranch - Blue Bird Loop, DeLonde Trail YesTelar XP Spot spraying for listed noxious weed species
2025/08/1208/12/20252025/08/2208/22/2025PierceNoEcomazapyr 2SL, ClearcastSpot spraying for eradication species hairy willowherb and purple loosestrife
2025/08/1208/12/20252025/08/2208/22/2025Hodgson Harris Reservoir YesEcomazapyr 2SL, ClearcastSpot spraying for eradication species hairy willowherb
2025/08/1208/12/20252025/08/2208/22/2025Flagg ParkYesEcomazapyr 2SL, ClearcastSpot spraying for eradication species hairy willowherb
2025/08/1208/12/20252025/08/2208/22/2025Heil Valley RanchYesEcomazapyr 2SL, ClearcastSpot spraying for eradication species hairy willowherb
2025/08/0508/05/20252025/08/1508/15/2025Link Trail., Lagerman Reservoir and AHI Longmont FarmsYesEcomazapyr 2SL, ClearcastSpot spraying for eradication species hairy willowherb
2025/08/0608/06/20252025/08/1508/15/2025St Vrain Rd., Nelson Rd., Prospect Rd., 63rd St., 75th StYesEcomazapyr 2SL, ClearcastSpot spraying for eradication species hairy willowherb *STARTED & COMPLETED* 8/7/25
2025/08/0808/08/20252025/08/0808/08/2025Hyw 119, Dixon Rd, Gold Hill Rd, Sunshine Canyon Dr, Lefthand Canyon Dr, Nelson RdYesMilestoneStop spraying County and State roadsides for List A eradication species (Spotted Knapweed, Japanese Knotweed, Yellow Toadflax) and other listed species.
2025/08/0808/08/20252025/08/0808/08/2025Boulder Canyon DrYesEcomazapyr 2SLSpot spraying State HWY for eradication species Japanese Knotweed
2025/07/2807/28/20252025/08/0108/01/2025Caribou Ranch - Sherwood GulchYesMilestoneSpot spraying for listed species within the planned Sherwood Creek project site *COMPLETED 7/30/2025
2025/07/2807/28/20252025/08/0108/01/2025Heil Valley RanchYesQuinstar 4LSpot spraying for eradication species leafy spurge. *COMPLETED 7/30/2025
2025/07/2107/21/20252025/07/2407/24/2025Agricultural Heritage CenterYesEscort XP Dupont, Vista XRT, SulfentrazoneSpot spraying for listed weed species Whitetop and kochia. *only spot sprayed Escort XP for whitetop, no other herbicide used.
2025/07/2107/21/20252025/07/2407/24/2025Lagerman Agricultural Preserve on the Open Sky LoopYesMilestone, Escort XP DupontSpot spraying for listed weed species Canada thistle, musk thistle, common tansy, common teasel. *Correction* Herbicides used - Milestone and Telar XP
2025/07/2207/22/20252025/07/2507/25/2025Meeker Sort Yard YesMilestoneSpot spraying for eradication species meadow hawkweed *COMPLETED 7/22
2025/07/2207/22/20252025/08/2208/22/2025Dake (off Sugarloaf Rd.)YesMilestoneSpraying for eradication species common tansy *RESCHEDULED 7/22 due to plant phenology - not yet flowering *CORRECTION Telar XP will be used
2025/07/2207/22/20252025/07/2507/25/2025Walden PondsYesEcomazapyr 2SLSpot spraying for eradication species garden loosestrife *COMPLETED 7/24
2025/07/2207/22/20252025/07/2507/25/2025Walden PondsYesTelar XP Spot spraying for eradication species yellow toadflax *COMPLETED 7/25/2025
2025/07/1807/18/20252025/07/1807/18/2025KraftYesQuinstar 4LSpot spraying for eradication species leafy spurge *Canceled due to weather conditions
2025/07/1707/17/20252025/07/1707/17/2025Sugarloaf Rd., Sugarloaf Mountain Rd., Sunshine Canyon Dr., HWY 72YesQuinstar 4LSpot spraying for eradication species spotted knapweed *Correction - chemicals used will be Milestone, Tordon 22k, Rejuvra *Completed 7/17/2025
2025/07/1407/14/20252025/07/1807/18/2025Heil Valley RanchYesQuinstar 4L, Tordon, Milestone, RejuvraSpot Spraying for Listed Species: Leafy Spurge, Knapweed, Jointed Goat Grass *Completed 7/17/2025 *Note - Joined goat grass control was not completed and will be done later
2025/06/3006/30/20252025/07/0307/03/2025South Boulder Rd, Valmont Rd, Airport RdYesPlainview SC, Vista XRT, Chlorsulfuron 75Spray treatment of Road Medians for safety and infrastructure integrity. *COMPLETED* 7/3
2025/06/2306/23/20252025/07/1807/18/2025OverBrook TrailYesQuinstar 4LSpot Spraying for eradication species Leafy Spurge *Canceled due to weather conditions
2025/06/2306/23/20252025/07/1807/18/2025OverBrook TrailYesMilestoneSpot Spraying for eradication species Russian Knapweed *Completed 7/11
2025/06/2306/23/20252025/06/2606/26/2025Mayhoffer Singletree TrailYesMilestone, Telar XPNOTE: IN PROGRESS Knapweed, scotch thistle, hoary cress, musk thistle, canada thistle. Spot spraying for noxious weed suppression.
2025/06/2306/23/20252025/06/2606/26/2025Schoolhouse Loop at Heil Valley Ranch YesMilestone, Telar XPNOTE: POSTPONED Poison hemlock, musk thistle, canada thistle. Spot spraying for noxious weed suppression.
2025/06/1106/11/20252025/06/1106/11/2025South Boulder RdYesPlainview SCMedian spraying in conjunction with Road Maintenance for infrastructure safety. *COMPLETED* 6/11
2025/06/0206/02/20252025/06/0606/06/2025Carolyn Holmberg Preserve at Rock Creek FarmYesEcomazapyr 2SLThe Boulder County Agricultural Division will be doing a dam infrastructure protection treatment at Stearns Lake. *COMPLETED 6/4/2023
2025/06/0406/04/20252025/06/2006/20/2025Heil Valley RanchYesQuinstar 4LSpot spraying for eradication species Leafy Spurge. Application will occur during the morning and be finished before 10 am. *RESCHEDULED 6/4 due to weather *RESCHEDULED 6/10 due to staff capacity *COMPLETED 6/18
2025/06/0206/02/20252025/06/0506/05/2025Mayhoffer (Superior) - Coalton and Meadowlark trailsYestelar, milestone, vistaSpot spraying from truck-mounted sprayer to treat curly dock, thistles, diffuse knapweed.
2025/05/3005/30/20252025/05/3005/30/2025Boulder County FairgroundsYesPlainview SC & Quinstar 4LTreatment of weeds around demonstration plot infrastructure and walkways. *COMPLETED* 5/30
2025/05/2705/27/20252025/05/3005/30/2025Boulder County ROWYesMilestoneSpot spraying for eradication species: Russian Knapweed *COMPLETED* 5/30
2025/05/3005/30/20252025/06/1306/13/2025OverBrook TrailYesQuinstar 4LSpot spraying for eradication species: Leafy Spurge *RESCHEDULED 5/30 due to staff capacity *CANCELED 6/13 due to staff capacity
2025/05/1205/12/20252025/05/1505/15/2025Hall Ranch 2NoMilestone and TelarTreating diffuse knapweed, dalmatian toadflax, houndstongue, thistles, burdock, hoary cress, flixweed, sulfur cinquefoil
2025/05/1605/16/20252025/05/1605/16/2025Boulder County ROWYesTordon 22KSpot spraying for eradication species: Russian Knapweed *STARTED & COMPLETED* 5/16
2025/05/1605/16/20252025/05/3005/30/2025Boulder County and State Highway ROWYesQuinstar 4LSpot spraying for eradication species: Leafy Spurge *STARTED* 5/16 *EXTENDED* 5/16 *COMPLETED* 5/30
2025/05/0705/07/20252025/05/3005/30/2025Spring Valley Rd (Boulder)YesEcomazapyrCut 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.
2025/05/0505/05/20252025/06/0506/05/2025Monarch Park - Niwot TrailsYestelar, milestone, vistaTouch up spray treatment of curly dock, teasel, prickly lettuce, thistles to maintain integrity of ecological restoration project. *EXTENDED* 5/8 due to weather *STARTED* 5/14 *ESTENDED* 5/15 due to weather *EXTENDED* 5/29 due to weather
2025/04/2804/28/20252025/05/0105/01/2025Agricultural Heritage Center HWY 66YesEcomazapyrCut stump application to tree near building foundation to prevent tree/tree roots from damaging infrastructure. COMPLETED 05/01/2025
2025/04/2804/28/20252025/05/2305/23/2025Tommy Thompson - Rock Creek TrailYesTelar and VistaSpray treatment of curly dock, teasel, kochia, thistles, hoary cress for suppression *STARTED* 4/29 *POSTPONED* 5/8 due to weather *COMPLETED* 5/14
2025/05/2805/28/20252025/05/2305/23/2025Ruth Roberts - Ruth Roberts Connector TrailYesTelar and VistaSpraying 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
2025/04/2104/21/20252025/04/2404/24/2025Monarch ParkYesTelar and VistaSpraying for curly dock, teasel, musk thistle. *COMPLETED 4/23/25*
2025/04/1404/14/20252025/04/1704/17/2025Hall MeadowsNoTranslineApplication to control diffuse knapweed and increase the biodiversity of a restoration site.
2025/04/1004/10/20252025/04/1004/10/2025Cemex Stone Canyon PropertyNoTranslineEarly season treatment for Diffuse Knapweed to enhance biodiversity and preserve significant natural communities. *Rescheduled from 4/8 to 4/10. *Completed on 4/10
2025/04/0704/07/20252025/04/1004/10/2025Golden Fredstrom (Near St. Vrain Rd and 75th St.)NoTelar - 1.5 oz/acre, milestone - 5 oz/acreApplication to control teasel, houndstongue, Canada thistle, bull thistle, common mullein, diffuse knapweed. Completed on 4/10/2025
2025/04/0704/07/20252025/04/1104/11/2025Carolyn Holmberg Preserve at Rock Creek FarmYesImazpyrStump 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
2025/08/0408/04/20252025/08/0508/05/2025County Roads North of Hwy 66 between East Countyline Rd and 75th St.These Roads are being mowed as part of our general county roadside mowing routes for vehicle, cycling, pedestrian and wildlife safety.
2025/06/2506/25/20252025/06/2606/26/2025Ogallala, Jasper Rd, 119th St & Arapahoe, Lakota, Isabelle Rd, Oxford Rd, Niwot Rd, Lookout Rd. 63rd St., Blue Mountain Rd, Apple Valley Rd, N 55th StThese Roads are being mowed as part of our general county roadside mowing routes for vehicle, cycling, pedestrian and wildlife safety.
2025/06/2306/23/20252025/06/2406/24/2025East County Line Rd, Kenosha Rd, N 115th St., 109th St., Roads West of Niwot (Oxford Rd., Nimbus Rd., Nebo Rd., Plateau Rd., 39th St., 41st St., 49th St., 77th St.)These Roads are being mowed as part of our general county roadside mowing routes for vehicle, cycling, pedestrian and wildlife safety.
2025/06/1806/18/20252025/06/1806/18/202595th from south of Plateau, Isabelle rd., BC road of way safety. Be beware of grass clippings on road.
2025/06/1606/16/20252025/06/1706/17/202565th St. North of Nelson Rd., Plateau Rd. near Lagerman res, 55th St./Ouray - South of Nelson Rd., East County Line Rd. - south of HWY 66, N 119th St., Prospect Rd., Pipit Rd., Oxford Rd. - East of US 287Boulder County ROW Roadside safety operations
2025/06/1206/12/20252025/06/1206/12/2025St. Vrain Rd, All road between Hygiene Rd and Nelson RD (49th ST, 51 ST, 59th ST, 65th ST, Crane Hollow RD)These Roads are being mowed as part of our general county roadside mowing routes for vehicle, cycling, pedestrian and wildlife safety.
2025/06/0406/04/20252025/06/0506/05/202563rd Street from Nelson to Diagonal (119); Niwot/Neva Road to Highway 36, 63rd Street to Highway 36. These Roads are being mowed as part of our general county roadside mowing routes for vehicle, cycling, pedestrian and wildlife safety.
2025/06/0206/02/20252025/06/0406/04/2025Boulder County ROW in both the north and south part of the county119th and Arapahoe Rd, Flagg, Dillon RD. 75th, 87th, 95th, and Woodland north of State Highway 66.
2025/05/2805/28/20252025/05/2905/29/2025Boulder County Maintained Roads between Boulder and Louisville and between Erie and LafayetteCherryvail Rd, Marshall Rd, S 66th St., 76th St, South Boulder Rd, Dillon Rd, Jasper Rd, 119th and Arapahoe.
2025/05/1905/19/20252025/05/2205/22/2025East Boulder County. South of HWY 52 & Niwot Rd.
2025/04/2804/28/20252025/05/0205/02/2025County 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 on non-agricultural open space areas. 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
2025/05/1905/19/20252025/05/2305/23/2025Hall Ranch Quarry Site NoMilestoneA 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