Efficacy of brush management via chemical methods can vary depending on target species and application conditions. This information is meant as a brief, general introduction into the method itself with no herbicide warranty or guarantee, express or implied. Always read and follow instructions provided on the herbicide label, and please consult the herbicide manufacturer and/or your local Cooperative Extension Agent for additional guidance. 

Managing brush with herbicides can be one of the more cost-effective options compared to other methods (e.g., biological, mechanical, cultural). Available funding aside, herbicides may be the only management option depending on site access for machinery, presence of sensitive archeological resources, and fuel resources to carry a prescribed fire. When the decision has been made to apply herbicide for brush management, the number of trees or shrubs per acre (or stems/acre) is a helpful metric in estimating costs. Secondly, the mode of application to meet the herbicide treatment goal should be considered. The most common herbicide treatment methods are Individual Plant Treatment (IPT) and broadcast/aerial application. IPT is typically used for small acreage treatments or for maintenance/follow-up of a larger brush treatment with backpack sprayers, UTV/ATV-mounted sprayers, or by cut-stump and/or basal bark application methods. Broadcast applications are used in landscape-level treatments with the use of aircraft or heavy machinery/tractors to apply herbicide quickly over a large area. When using a sprayer, appropriate nozzle size selection and application rate calibration is needed to ensure the approved, safe amount and coverage of herbicide is applied.   

Herbicides can be in liquid, powder, and pelletized forms depending on target species and selected application methods (e.g., IPT vs broadcast). The most common herbicides used to treat brush specifically are triclopyr, picloram, tebuthiuron, and clopyralid. When in liquid form, these herbicides can be used individually or in a mixture to maximize treatment efficacy. Applicators often mix herbicides with oil-based additives to increase herbicide-plant contact and ensure thorough plant coverage. Each shrub and tree species may react differently to a particular herbicide and formulation, where specific formulas may already exist to match the herbicide(s) to the target brush species. With the soil, climate, and plant community variation on rangelands, land managers and owners are encouraged to reach out to their local Weed Management Area and county Cooperative Extension agents for species-level herbicide guidance.  

For more detailed information on herbicides, see the Herbicides topic page.