In this issue:
- Seasonal Weed Control Reaps Year-Long Results
- Safety Drives Michigan DOT Roadside Program
- Stop Winter Annuals in the Fall
- Trial Shows Exceptional Weed Control and Grass Safety
Click the “Sign Up Now” button to start receiving customized Weed Wise information via e-mail.
Seasonal Weed Control Reaps Year-Long Benefits
The right timing for herbicide applications is essential when it comes to effective broadleaf weed control. Treating weeds at key growth cycles not only maximizes control but also makes crews more efficient.
“Some of the most troublesome perennial weeds, including Canada thistle, wild carrot and chicory, stay green well into fall, sending nutrients to their root systems and storing them for spring,” says Matt Kraushar, Purdue University’s Habitat Specialist. “That makes fall an opportune time for residual herbicide control by hindering the weed’s process for overwintering and dormancy.”
Fewer spring weeds, delayed mowing
Fall application helps limit spring weeds and can extend mowing cycles, Kraushar adds.
“By killing most perennial broadleaf weeds in the fall, only new germinating seedlings will be present in the spring. Those seedlings are less vigorous than older, established perennial plants, making them easier to control,” he explains. “Using herbicides with residual activity can also help keep germinating seedlings from becoming problematic.”
Depending on the herbicides included in the program, fall applications not only control spring broadleaf weeds, but can reduce spring grass growth through plant growth regulation, Kraushar notes. “This can push the first mowing cycle to later in the spring, which keeps mowers out of early rain-soaked, soft terrain and frees up crews for other spring tasks. Roadside managers may be able to eliminate an entire mowing cycle, since quick grass regrowth and broadleaf weeds are no longer a big concern.”
Keeping roadside weeds under control throughout the year adds several layers of benefits for the public and maintenance crews. For motorists, seasonal roadside weed control means better sightlines for spotting potential hazards at greater distances. For road crews, it means less time on the roadways.
“Mowers travel at 3 to 5 miles per hour and are constantly moving around signs, barriers, culverts and other obstacles that put them in close proximity to motorists,” Kraushar says. “A side-spraying herbicide application truck travels about 10 miles per hour, with less weaving around obstacles, which greatly reduces the time crew members spend on the road near traffic.
“Short-term control measures can end up costing maintenance departments more in the long run due to return visits for mowing or respraying,” Kraushar adds. “With the development of newer residual herbicide options from DuPont and other manufacturers, fall has become an ideal time to treat weed species.”
Safety Drives Michigan DOT Roadside Program
Roadside maintenance programs get complicated when you’re in charge of 10,000 miles of highway. But for Todd Rowley, vegetation technician for the Michigan Department of Transportation, it all comes down to one thing: safety.
“Our program revolves around safety,” Rowley says. “With today’s budget limitations, everything we do has to have a safety factor attached to it, whether it’s bareground, broadleaf or brush control.”
Grassy weeds, such as tall-growing phragmite, and brush that block motorists’ vision and expressway slide-off areas are given top priorities in Rowley’s program. His department also works to maintain a healthy turfgrass stand along roads to promote reduced erosion and maintain road structures, which has been critical during the torrential rains of the past few seasons.
Rowley prefers to treat weeds in the fall when they’re most susceptible to herbicides. “Because our state is so large and our staff has been reduced, we have to start applying herbicides after July 4 and continue through fall. Even though we have to start a little earlier than we’d like, we’re still getting good results with the newer products we’ve been able to use.”
One new weed that has gained a foothold in Michigan is kochia. Rowley has been testing DuPont™ Perspective® herbicide for kochia control and has seen good control. He’s also had good results when testing DuPont™ Streamline® and DuPont™ Viewpoint® herbicides on brush species including poplar trees, cottonwood, maples and others.
“Along with funding shortages, one of our department’s biggest challenges is the explosion of noxious weeds,” Rowley says. “Having the ability to be flexible and tackle new challenges on the spot has become important. For safety reasons, we don’t have time to put off weed problems or they will take over.”
Stop Winter Annuals in the Fall
One effective option for controlling winter annual weeds such as curly dock, thistles, dandelion, goldenrod, marestail, buckhorn plantain and others is a strategic fall herbicide treatment.
DuPont™ Perspective® herbicide offers flexible application timing, including fall applications for weed control into the following spring. Benefits include:
• Stops explosive growth of tough winter annuals
• Helps preserves desirable native perennial grasses
• Delays or eliminates early-spring mowing and reduces application costs associated with early-season weed control
• Inhibits seedhead formation and suppresses grass growth for delayed mowing pressure in the spring
• Allows crews to balance spraying programs with other roadside duties
Trial Shows Exceptional Weed Control and Grass Safety
A roadside weed control and grass safety trial conducted in South Vienna, Ohio, compared Perspective® with Opensight and Milestone treatments. The results showed highly effective control of several tough weeds and no effect on desirable grasses at 281 days after treatment with Perspective®.
Perspective® Controls Roadside Weeds