Field bindweed, Johnsongrass and sericea lespedeza are three wide-ranging, difficult perennial weeds that can be controlled in the fall, says Jeff Ball, a soil and crops specialist at the Noble Foundation in Ardmore, Okla. As these weeds accumulate carbohydrates in their roots before going dormant for the winter, herbicides applied will travel to the roots as well, killing them or greatly reducing vigor in the spring.
“Bindweed is aggressive and causes a tremendous amount of yield loss annually in wheat,” Ball says. “The best method of control is to apply Roundup or a generic equivalent or LandMaster in a timely manner through the summer fallow period. The last application should be made after planting wheat two weeks before the first killing freeze.”
In the southern United States, Johnsongrass can cause severe yield loss in both pastureland and row crop operations.
“Control is difficult since it is a grass weed growing in a grass crop,” Ball says. “However, in row crop production, several herbicides available control it. Pastureland is a different story. We recommend using a weed wiper loaded with glyphosate.”
Sericea lespedeza is a weed able to grow no matter the environmental conditions, allowing it to out-compete more desirable grass species.
“Mowing and burning won’t control Sericea. In fact, it responds favorably to fire and tends to spread after burning,” Ball says.
Ball recommends applying either Cimarron or Cimarron Max any time in the fall.
Ball adds that fall also can be an excellent time to control brush using a basal bark treatment, which involves applying a 15 percent to 25 percent Remedy/diesel solution to the trunks of the targeted brush species. The solution should be applied 12 to 15 inches above the soil surface and 360 degrees around the trunk.
“Brush is a different battle from herbaceous weeds, though, and it’s typically not a one-year thing,” he says. “Odds are that you will get above 70 percent control with a basal bark treatment. If I got 80 percent control after one application, I’d be tickled.”