With the bad Virginia buttonweed and doveweed infestations this year, I have been itching to give the go-ahead on using cool-season herbicides. Well, the time has finally come, thanks to the cool front that pushed through this week.
The irony is, we can’t apply a treatment until we get a dry day.
The “cool-season” herbicides I’m referring to include products like Ferti-lome’s Weed Free Zone and Bonide’s Weed Beater Ultra. They are great tools for knocking out certain weeds once our high temperatures consistently drop below 80 degrees.
By the way, cool-season herbicides don’t work below 40 degrees, either. So, 78-40 degrees is the proper temperature spread.
Years ago, before the advent of cool-season herbicides, broadleaf weed control in December, January and February was pretty much non-existent. That’s because standard broadleaf weed controls that are used in the spring and summer can actually kill St. Augustine and Bermuda lawns if applied at the wrong time of year. Conversely, cool-season herbicides used when it’s too warm can do lots of damage, too.
So, along came carfentazone-based Weed Free Zone and Weed Beater Ultra, and the art of weed control in cooler months is now perfected. Still, there are some caveats to be respected for these herbicides to work properly. Because most water along the Gulf Coast is so hard, you must understand the importance of adding surfactants, to give herbicides the ability to stick to the weeds. Without a surfactant such as Bonide’s Turbo Spreader Sticker, the herbicide will just bead up and roll right off the weeds’ leaf surfaces and into the soil.
Also important is how a herbicide is applied. I highly recommend spot treating. Since most herbicides are sold as concentrates, the best tools for spot treating are pump-up sprayers or hand-held trigger sprayers. I suggest avoiding dial-and-spray or ready-to-spray bottles that you hook to the end of a hose, because you can’t be as precise with them. If ready-to-spray formulas are the only types you can find, please use them with extreme caution – limit their use to spot treatments only. You’ll need to be quick with the on-off switch because overuse on the entire yard can cause the grass to yellow.
And one final reminder about cool-season herbicides: they are specifically for broadleaf weeds. They will not control “grassy” weeds. But if you have things like clover, you have permission to spot treat with those carfentazone-based herbicides.