Herbicides for Fencerows and Farmsteads

Every so often, we receive calls about the use of herbicides under fencerows and around various structures on the farmstead (e.g., barns, poultry houses, manure pits, greenhouses, non-grazed fencerows, ditch banks, unpaved lanes, etc.). There are actually numerous products labeled for these utilities. However, when using herbicides around fence lines, it is necessary to know about any grazing or haying restrictions associated with each product. Also, understand what types of weeds (e.g., grasses, broadleaves, woody, etc.) will be controlled by each herbicide and how long soil residual activity can be expected, if at all.

Typical herbicides such as glyphosate, 2,4-D, dicamba, and Crossbow can be used but will likely need to be tank-mixed with each other to provide broad-spectrum control. However, none of these above provide residual activity, so expect to respray after several weeks as new weeds start to invade. Herbicides such as Arsenal, Pramitol, Solicam, Spike, and Rezilon/Esplanade could be mixed with the above products to provide long soil residual activity (few to several months or more) and can control a variety of weeds, but some cannot be used under fences that confine livestock. Refer to Table 2.6-19 (below) in the 2026 Penn State Agronomy Guide for information about these herbicides and others that can be used in these settings. This table lists information about types of weeds each will control, as well as grazing and haying restrictions associated with them.

Another consideration regarding fencerow applications is the amount of total area that will be sprayed and, thus, how much spray solution to mix. For example, if you plan to spray a 1-foot band under the fence or around structures, the distance required to treat one acre equivalent would be 43,560 feet or 8.25 miles. If the spray band is 3 feet wide, then 14,520 feet or 2.75 miles would be required to treat an acre.

This table lists several herbicides available for use in farmstead areas. Farmstead areas may include areas around buildings (storage buildings, poultry houses, greenhouses, etc.), nongrazed fencerows, non-irrigation ditch banks, unpaved lanes, or other non-cropped agricultural areas where selective weed control or bare ground is desired. Some herbicide labels allow grazing or haying of treated areas within or around these sites, while others do not. Many of these herbicides are toxic to desirable plants when spray particles contact either aboveground plant parts, bare roots, and/or the soil where plant roots have penetrated. Most of these products should not be used on impervious surfaces such as paved or highly compacted areas. Runoff from treated impervious surfaces or transport of treated soils by erosion can severely injure or kill susceptible non-target plants. Do not apply these products directly to water, and exercise caution when using these products near irrigation or domestic water supplies. Many of these products are not recommended for use on highly permeable soils and/or soils with groundwater near the soil surface. Read herbicide labels carefully to determine allowed uses, environmental risks, human risks, desirable plant species tolerance, weed species susceptibility, application types, use rates, adjuvant requirements, and specific grazing or haying restrictions.
1 Herbicides listed as having limited soil residual activity may, for a short time, provide residual control or suppression of some species and can injure or kill susceptible desirable plants through soil activity.
2 NS = next season after application.
3 Not on all metsulfuron labels.