By Clint Thompson
University of Georgia, College of Agricultural and Environmental Sciences
Waiting for a weed to become a problem before applying adequate control is the wrong approach for tackling weeds like thistles, dandelions and henbit, says Larry Baldree, a UGA crop and soil sciences research professional who works in Tifton, Georgia, alongside UGA turfbreeder Brian Schwartz.
“It’s being proactive instead of reactive. A lot of times, we’re very reactive to things, but when you see lawns that are weed-free, (those homeowners) are being very proactive. They’re getting a light application of fertilizer down in early fall and then getting their pre-emergence herbicide down now,” Baldree said.
To effectively manage winter weeds, Baldree suggests using a rate of atrazine of about a quart per acre. Two applications per year, though, are needed to prevent weeds from getting out of control.
“Atrazine will keep your weeds down throughout the fall. You’ll also want to do an application in late February as well, to control summer weeds. It’s got about a four-month activity period,” he said. “Making an application twice a year is the best management approach to take.”
Baldree issued the weed control directive just as weeds like thistles and dandelions are becoming problematic. A thistle is a prickly looking plant that can become tall and unpleasing to the eye. Baldree says that thistles left untreated will become a bigger problem in the following year.
“If you allow them to seed out one year, the next year you’re going to have numerous plants. Any preventative maintenance you’re doing now is going to be preventative maintenance for the future as far as keeping the seed crop down,” Baldree said.
He says the best time for weed control and fertilizer applications in lawns is during September and October. While the time to “weed and feed” has passed, Baldree stresses that there is still time to apply appropriate weed control.
“Atrazine is a triazine product. It inhibits the seed and keeps it from germinating,” Baldree said.
Baldree stresses that atrazine should not be used on cool season grasses, like tall fescue lawns in north Georgia.