Western weed pressure

Northern states in the Midwest region may better relate to weed pressures experienced to the Northeast, while closer to the transition zone in Kansas, spring’s “entrance” can vary up to six weeks and has a significant impact on what turf and ornamental issues LCOs will experience.

Here are some issues to keep on the radar in the Midwest:

Winter annual broadleaf weeds: During the first quarter, warm-season turfgrass can use a “winter weed cleanup” with a non-selective glyphosate – it’s safe because the grass is dormant, says Jared Hoyle, extension turfgrass specialist at Kansas State Research and Extension.

Crabgrass: Now is the time to think about applying a pre-emergent herbicide to prevent crabgrass, Hoyle says. “A good rule of thumb for crabgrass application is around April 15,” he says, noting that an average 55-degree temperature is ideal. “By May, crabgrass germinates."

Dandelion: Catch them pre- or post-bloom. Research conducted at Kansas State University showed that timing is critical when using broadleaf herbicide to control dandelion. “You definitely want to avoid a peak-bloom application,” Hoyle says, explaining that the bloom essentially sucks up the product, leaving its stem and roots virtually untreated. “You won’t get as effective control during this time.”

West.

Weeds and disease are less of an issue in the arid West and southern California than drought. Lack of water drives turf and plants into stress mode, says James Baird, turfgrass specialist at University of California Riverside. “It has been so dry here that disease has not been a problem,” he says. Weeds are another story. “With more restrictions on watering, weed pressure is going to be at a premium.”

Crabgrass: What’s important to note out West is the earlier timeframes for applying pre-emergent herbicides, Baird says. January and February are prime times for spreading a crabgrass preventive and controlling summer annual weeds.

Summer annual weeds: “We have so many species that seem to be localized, and even what we see one year may not be present another year,” Baird says. Pre-emergent applications are important, and now’s the time he says.