Successful weed and brush control doesn't start in the spring. It starts now, with proactive fall herbicide applications.
The Change of Seasons
Football is back, and leaves are starting to drop across the country. With the changing of the season comes a renewed opportunity to control undesirable vegetation. By combining a few adjustments in technique and product selection, vegetation managers can extend their treatment window, deliver results, and set themselves up for success next growing season.
Decreasing Temperatures, Increasing Results
BARE-GROUND APPLICATIONS
Fall herbicide applications can be highly effective, especially in regions with cold to moderate winters. Cooler soil temperatures slow herbicide breakdown, allowing residual herbicides to persist into spring and early summer. Trials from Colorado State University show the longevity of control is similar between fall and spring applied programs at the same evaluation intervals throughout the season. Alligare’s newest products, Ballast and Mainline, were included in these studies with excellent results. It is important to note that fall bare-ground applications must be made before the soil freezes, and herbicides should never be applied to frozen or snow-covered soils.
SELECTIVE APPLICATIONS
Selective fall applications are beneficial for controlling winter annual weeds. Winter annuals germinate from late summer through early winter and grow actively in the spring. Post-emergent herbicides are effective for weeds that are up and actively growing. While post-emergent herbicides can work, products that provide both pre- and post-emergent activity, like Alligare’s Whetstone, are preferred for extended control. This is especially important in warmer climates with longer germination windows. Similar to fall bare-ground programs, in colder regions, residual activity often also helps suppress early germinating summer annuals.
No Leaves, No Problem
The turning of the calendar also provides an excellent opportunity to control woody species like small trees and brush. Woody plants are susceptible to herbicides year-round when proper application techniques are used, even deciduous species that have entered a state of dormancy. Vegetation managers have options when it comes to controlling dormant trees and brush. When making a decision on what technique should be used, the size and density of the target species should be considered, as well as surrounding desirable vegetation and infrastructure.
BASAL BARK APPLICATIONS
Basal bark applications are ideal for plants up to six inches in diameter and when there are fewer than 500 targeted stems per acre. This method includes mixing herbicide(s) with oil to carry the product through the bark, into the vascular tissue, and ultimately into the root system of the plant. To maximize efficacy, the solution must be sprayed onto the lower 12 - 15 inches of the stem/trunk down to the soil line, including all exposed flare roots. For multi-stemmed species, all stems should be treated. This method allows the applicator to selectively treat individual plants, reducing potential injury to neighboring vegetation. These applications are extremely useful in sensitive environments and in areas where the "brown-out" associated with traditional foliar applications may be deemed unacceptable. When performing basal bark applications, Alligare recommends mixing Triclopyr 4 at 25 percent in oil using a backpack sprayer or handheld, pressurized spray bottle as the preferred delivery system for the herbicide solution.
DORMANT STEM APPLICATIONS
Dormant stem treatments can be used to control susceptible woody plants and vines with stems less than two inches in diameter. Similar to basal bark applications, the spray solution is absorbed through the stems and branches of the target species and then translocated to the root system. This application method works best in dense areas and when trees and brush are less than 10 feet tall. Plant stems can be treated with both low-volume and broadcast applications. In these instances, mixing triclopyr ester with crop oil concentrate or methylated seed oil in water has been proven to be an effective solution. Consider adding Alligare’s Whetstone to the mix to expand the spectrum of species controlled. Dormant stem applications provide vegetation managers an excellent tool to expand the treatment window and are a preferred method of application by many departments of transportation due to the reduced "brown-out" effect along roadsides.
CUT-STUMP-TREATMENTS
Cut-stump treatments involve cutting down a targeted plant and then applying an herbicide solution directly to the stump surface. This is an effective way to prevent the regrowth of woody species and large vines. For multi-stemmed species, all stems should be cut and treated. As a best practice, cut as close to the ground as possible, leaving a one to two-inch stump. For stumps and stems smaller than six inches in diameter, the entire cut surface should be treated. For larger species, the most critical area of the stump to treat is the cambium, which is the layer just inside the bark. If the herbicide is being applied immediately after cutting, the most common solutions involve mixing glyphosate or Triclopyr 3 at a 50 percent rate in water. For older cuts, a 25 percent solution of triclopyr 4 ester in basal oil can be used; however, the entire root collar (bark area) and any exposed roots must also be treated. Cut-stump treatments are ideal in urban settings and in right-of-way environments where dead plant material may pose a safety risk.
Overgrown vegetation threatens infrastructure and industrial facilities year-round. By adjusting application strategies in the fall, vegetation managers can keep control efforts effective, extend protection into spring, and maintain safer, cleaner sites.
