Applications Applicators have a number of techniques available to them when applying herbicides. It’s important to first select the technique best suited to the vegetation and use site you intend to treat, as well as the herbicide(s) you intend to use. Once the method is selected, it’s equally as important to understand and carry out the application correctly to ensure maximum efficiency in controlling target vegetation.

Broadcast applications

When infestations of invasive or non-native plants are too dense (>150 plants per acre) or areas are too vast to use more selective application methods, a broadcast herbicide application may be required. This application method is suitable for invasive plant management, roadside selective weeding or site prep when using herbicides with appropriate selectivity to native or desirable species that may be present. Depending on the situation, there are many equipment types available for mounting broadcast application systems, including all-terrain vehicle mounted sprayers, tractor-mounted sprayers and roadside sprayers.

Broadcast application basics

  • Always read and follow label directions
  • Keep ground-rig booms high enough to clear foliage and provide suitable coverage, but low enough to minimize the chance of drift
  • Calibrate equipment to ensure precise application and economical use of herbicide
  • Maintain constant ground speed and sprayer pressure
  • Apply an adequate total spray volume to ensure good coverage
  • Foam markers can help avoid skips or excessive overlaps

Foliar applications

Individual foliar treatments are limited by stem density and height, and are ideal for maintaining a site after an initial reclamation. Low-volume foliar treatments are appropriate for stem densities of 1,500 or less, and stem heights shorter than 7 feet. High-volume broadcast treatments, usually done with powered sprayers, hoses and handguns, can treat stem densities of more than 1,500 and heights higher than 7 feet. Use a high-volume handgun treatment to knock back high-density areas of brush and a follow-up low-volume individual foliar treatment to eliminate undesirables after the initial reclamation.

With Vastlan* specialty herbicide, you can make foliar applications across the widest array of vegetation management sites, including aquatic settings. For increased efficacy on a broader spectrum of annual, biennial and perennial weeds and brush, utilize a tank-mix of Vastlan and Milestone® or Opensight® specialty herbicides.

*Vastlan is not yet registered with the U.S. EPA. Federal registration is pending. The information presented here is to provide technical information only and is not an offer for sale of product.

Foliar spraying application basics

  • Spray herbicide directly onto foliage of individual plants.
  • Use spray pressures and techniques that minimize spray drift.
  • Get good coverage on the growing tips and terminal bud.
  • Spray all sides of the target plant to ensure adequate coverage.
  • Apply the herbicide solution at a volume the wets the foliage, but not to the point of runoff.
  • Make treatments during period of active growth. Early season applications work best after full leaf-out or target brush. Late-season applications work best before target plants’ leaves show fall colors.

Video: Low-volume foliar applications

This video reviews the correct way to apply herbicides using a low-volume foliar technique.

Cut-surface applications

Cut-surface applications are efficient and can be made quickly and easily. They are effective for controlling individual trees along distribution lines and can extend maintenance cycles. Using the cut-surface method on a site that is being mechanically cleared allows the herbicide to prevent resprouting. If treating highly visible areas, there is no unsightly brownout when foliage dies, since only the stumps are treated.

Different forms of cut-surface applications include cut-stump, basal cut-stump, cut-stubble, hack-and-squirt and injection applications. Cut-stump treatments are the most popular, so consider Pathway® specialty herbicide, a convenient ready to use formula specifically designed for cut-stump treatments, or a 50% dilution of Vastlan™* in water. For basal cut-stump applications utilize Pathfinder® II specialty herbicide a convenient ready to use oil based formulation, or a mixture of Garlon® 4 Ultra specialty herbicide in any commercially available basal oil mixture.

*Vastlan is not yet registered with the U.S. EPA. Federal registration is pending. The information presented here is to provide technical information only and is not an offer for sale of product.

Video: Basal Cut-stump treatment with Garlon 4 Ultra in oil

Basal cut-stump treatments are highly effective for controlling trees or brush. This video goes over how to apply a low-volume basal mix of Garlon 4 Ultra in oil to cut stumps.

Video: Cut-surface with water-based herbicide mixture

This video explains the proper technique for applying a water-based herbicide to a cut surface.

Water-based cut-surface application basics

  • Treat the surface as soon as possible after cutting.
  • If more than one hour elapses after cutting, switch to an oil-based herbicide application.
  • Treat only the cambium and outer 2 inches of sap wood (xylem) inside the bark around the entire circumference including down the trunk where the bark may have separated from the stump.
  • Exercise caution with soil-active herbicides to prevent off-site plant damage.
  • Applications can be made any time of the year, but should be done immediately after cutting but avoiding the spring for sap bleeding species like maples.
  • Consider Pathway or Vastlan* specialty herbicides.

Oil-based basal cut-stump application basics

  • Can be applied anytime after cutting, including winter months.
  • Do not make applications when snow or water prevents spraying to ground level.
  • Treat the cambium and outer 2 inches of sap wood inside the bark around the entire circumference and also the bark on the stump as well as any exposed roots around the stump to ground level, but not to the point of runoff.
  • Treat the entire circumference of the tree, including down and around rips in the bark.
  • To ensure effectiveness, treat exposed roots around the stump.
  • Applications can be made any time after cutting, including winter months, except when snow, ice or water prevents spraying to ground level.
  • Consider Pathfinder® II , a tank-mix of Garlon 4 Ultra and Milestone® or Garlon 4 Ultra specialty herbicides.

Video: Hack-and-squirt injection applications

Hack-and-squirt injection applications are effective in controlling trees and woody plants that are too large for basal bark treatments. This video demonstrates the proper technique to perform a hack and squirt to small, medium and large trees.

Low-volume basal bark applications

Low-volume basal treatments use a low rate of herbicide to control trees with stems less than 6 inches in diameter. This treatment method is highly efficient for treating long stretches of low-density brush on rights-of-way with fewer sprayer fill-ups. In some cases, an applicator can spray all day with 4 to 5 gallons of herbicide solution with very low plant densities. Low-volume basal treatments are more effective at selectively removing undesired vegetation and maintaining desirable plants, as opposed to mechanical methods, which are nonselective.

The name of Garlon® has long been the proven standard in basal bark applications. Consider Garlon 4 Ultra specialty herbicide or a tank-mix of Garlon 4 Ultra and Milestone® specialty herbicide for increased efficacy on multiple woody species. Refer to the product labels for directions on mixing an amine in oil. For a convenient ready to use product, Pathfinder® II specialty herbicide is the answer.

Low-volume basal bark application basics

  • Apply spray to the lower 12 to 15 inches of bark around the entire stem.
  • Spray until bark is wet, but not to the point of runoff.
  • Do not apply to bark that is wet or saturated from rain.
  • If herbicide/penetrating oil mixture turns white when applied to bark, it’s an indicator that the bark is too wet and the application will be less effective.
  • Can be used year-round, except when snow, ice or water prevents spraying to ground level.

Video: Applying low-volume basal

In this video, the proper technique for low-volume basal herbicide applications is reviewed, both to single stems and multiple stems in a clump.

Dormant-stem applications

Video: Dormant-stem applications

Dormant-stem treatments are ideal for controlling woody plants that are numerous and small (less than 6 to 7 feet tall) during late fall and winter. This video goes over proper application techniques for high-volume and low-volume dormant-stem treatments, and reviews their many benefits.

Combination mowing

Combination mowing is a one-pass treatment offered by a mower that cuts brush and weeds and applies herbicides at the same time. It provides a benefit for utility foresters and vegetation managers looking to improve control while saving time and money.

Combination mowing has its advantages:

  • There’s no wasting herbicide on debris that’s already been cut. Direct contact to cut stubble reduces the amount of herbicide used.
  • Separate mowing and application chambers increase efficacy.
  • A shielded application chamber eliminates the effects of wind drift and weather.
  • Using a one-pass treatment saves time and money.
  • Having less brush to cut back during annual mowing cycles speeds up the process and reduces the chances of mower damage.
  • Reduced brush also improves drainage of sideline and outfall ditches.
  • Brush will no longer block pipes and waterways.