It’s fairly simple to distinguish broadleaf weeds (part of the plant grouping dicotyledons, also known as dicots) from grassy weeds (part of the plant grouping monocotyledons, or monocots). The wider leaf structure of broadleaf weeds will stand out from desirable turfgrass. This physiological difference also makes broadleaf weeds easier to control with a selective herbicide than grassy weeds or sedges.
Broadleaf weeds can grow in all soil types, making them a very familiar presence in turf across the United States and beyond. Common broadleaf weeds include dandelions, ground ivy, buttonweed, doveweed and dollarweed. The majority of broadleaf weeds produce an abundant amount of seeds, some of which can persist in soil for more than 30 years. Broadleaf weeds are categorized based on their life cycle into the following groups: annual weeds, winter annuals, summer annuals, perennial weeds and biennial weeds.
Annual weeds are often the easiest broadleaf weeds to control, as their underground vegetative structures don’t propagate new plant growth. These weeds spread through turfgrass through prolific seed production. Summer annuals are arguably the most challenging, as these weeds germinate at varying times throughout the summer and mature quickly.
Dense, well-maintained turf is the best defense against broadleaf weeds. Fertilization, frequent mowing at 3.0-3.5 inches, proper irrigation and managing shade will all help turfgrass crowd out weed competition. Even with good cultural practices, broadleaf weeds can invade turfgrass. Preemergence herbicides should be applied in April to help reduce broadleaf emergence.
The best time to control postemergence broadleaf weeds is when weeds are young and actively growing. Make your applications on a clear day when temperatures are below 85 degrees, as excessive heat increases the risk of additional turf stress. Don’t mow treated turfgrass three days before or after your postemergence broadleaf weed treatment.
If you’re seeing broadleaf weeds (or any kind of weed, for that matter), try the handy FMC Herbicide Solution Finder to determine which product is best for your particular turfgrass type. Having trouble identifying which broadleaf weed you’re dealing with? Request a FREE Weed Identification Poster from FMC, available through September 30, 2012 or while supplies last!