Fall’s cool temperatures and resulting leaf drop can signal a sometimes-abrupt end to another foliar spraying season. And that transition won’t wait for all your rights-of-way (ROW) maintenance to be complete.
When spray treatment cycles are limited to the growing season, planned work must be done in a confined window of time. When you layer on unforeseen or uncontrollable inputs such as inclement weather, labor shortages or budget fluctuations even the best-laid plans can easily be derailed. It can result in vegetation managers playing a game of catch-up the following season, knowing that same work will almost certainly be more difficult and more costly to perform.
It was an all-too-familiar scenario for Corey Sweeney, contract services manager, power delivery, Alabama Power Company. Confining treatments to the foliar season meant his crews could sometimes struggle to complete maintenance cycles. And there were other opportunities he wanted to capitalize on.
“Herbicides are a key component of our integrated vegetation management program as they allow us to control incompatible woody species while at the same time enhancing native grasses and forbs on our rights-of-way,” Sweeney says. “But we weren’t able to implement herbicide applications using late-season money that came in. Also, we needed a better method to make herbicide applications in sensitive areas to help reduce customer complaints.”
The answer was dormant-stem treatments. These treatments are an effective and economical solution to address incompatible brush when treatment is postponed during foliar season. They can also reduce foliar-season spraying demands ― particularly useful in sensitive areas. Applications can be made later in the fall, throughout the winter months and even into spring, when many crews have put their spray equipment up until the next growing season, allowing you to capitalize on late-season funding that may materialize.
But what’s the catch? Most would assume it comes in lower effectiveness in comparison with foliar applications. But, as Alabama Power discovered, that wasn’t the case.
Change didn’t happen overnight.
It started in 2011, when Sweeney partnered with Corteva Agriscience to begin a series of what he calls trial-and-error experiments using dormant-stem treatments. “We really wanted to know how effective the control would be on our ROWs in comparison to foliar treatments,” Sweeney says.
If the control was there, then it opened the door to using dormant-stem treatments to begin addressing the ongoing challenges Sweeney saw in his ROW maintenance program.
Trial results proved positive and were backed by separate field data gathered by Corteva Agriscience. That data shows that utilities’ correct use of dormant-stem treatments consistently results in anywhere from 85% or better control on hardwoods such as maple and oak, as well as conifers such as pine. Along with mimosa, privet and tree-of-heaven, these trees are some of the more predominant species Alabama Power targets on its ROWs.
Dormant-stem treatments are now considered a key component of Alabama Power’s ROW maintenance program. Since implementation, these treatments have been applied on an increasing number of acres, to the point that Alabama Power estimates thatdormant-stem treatments were used on more than 52,000 acres from 2016 to 2018. And Sweeney has seen the benefits.
While Alabama Power found in its initial trials and in subsequent years of field work that dormant-stem control can serve to enhance its ability to manage incompatible woody species, Sweeney has also seen an increase in beneficial grasses, desirable forbs and shrubs that provide habitat for critical pollinator species and other area wildlife.
That was made possible in large part by Alabama Power’s decision to also incorporate selective herbicide technology into its dormant-stem treatments. But the more practical benefit is that releasing desirable vegetation to thrive provides a biological barrier of sorts against further woody plant establishment. And that’s saved on valuable time and resources needed for future treatment cycles.
“We currently use a low-volume application tank mix that consists of Garlon 4 Ultra herbicide at a rate of 6%, Milestone herbicide at 0.66%, imazapyr at 0.5% and a methylated seed oil at 2%,” Sweeney says.
While imazapyr is considered selective, it will control certain grasses. However, that is offset by applying it when grasses go dormant during the winter, allowing them to recover relatively quickly in the spring.
Dormant-stem treatments are most effective beginning at fall leaf drop and continuing until early bud break. That extended treatment window allows for a reallocation of work crews from later spring and summer to fall and winter, when most crews are shutting down.
The benefit comes from the ability to pick up where foliar crews left off. Otherwise, when crews halt work before completing treatment cycles, any skipped brush can grow an estimated 20% to 40% from one year to the next, which means more time and material will be needed to treat it. It also opens the door to access late-season budget dollars.
“We’ve found October through January to be the optimum timing,” Sweeney says. “That flexible late-season timing provides the opportunity to implement herbicide applications utilizing end-of-year money.”
Most people are unable to tell the difference between a dead tree and a dormant tree. When a herbicide application can be made during problem trees’ dormant periods, the public often assumes it just didn’t survive the winter. This can significantly reduce landowner complaints in comparison with growing season applications, when a much more noticeable brown-out occurs post-application.
A good example of this is Alabama Power’s agreement with the Alabama Department of Transportation (DOT). Sweeney has crews make dormant-stem treatments on highly visible distribution lines near roads. The treatments improved aesthetics due to reduced brown-out and have resulted in fewer complaints for both the Alabama DOT and Alabama Power.
Ask yourself if you wish you’d been able to do more this season. Then consider the additional benefits dormant-stem treatments can infuse into a utility ROW program. For Alabama Power, that’s meant extended application windows, more budget flexibility and fewer customer complaints.
™ ® Trademarks of Dow AgroSciences, DuPont or Pioneer, and their affiliated companies or their respective owners. When treating areas in and around roadside or utility rights-of-way that are or will be grazed, hayed or planted to forage, important label precautions apply regarding harvesting hay from treated sites, using manure from animals grazing on treated areas or rotating the treated area to sensitive crops. See the product label for details. State restrictions on the sale and use of Garlon® 4 Ultra and Milestone® apply. Consult the label before purchase or use for full details. Always read and follow label directions.
For over 30 years, Vistas® has covered strategies, trends and stories from across the Vegetation Management industry.