K-State’s newest Chemical Weed Control publication is a good guide

MANHATTAN, Kan. – A Kansas State University range management specialist says the state’s landowners are approaching a key window of opportunity for controlling three woody brush species that are prevalent in the state’s pastures.

Walt Fick said the species commonly found in the Kansas Flint Hills and parts to the west are buckbrush, roughleaf dogwood and smooth sumac. He said that if left unchecked, each of those is known to be highly competitive with grassland.

Those three species can be controlled, but the methods for doing so vary.

“Prescribed burning can help to a point,” Fick said. “But timing is quite important when we’re using fire. These woody plants have to be leafed out if we’re going to cause much damage. Of the three, buckbrush is the easiest to control with fire, because it’s the first to leaf out – typically in late April or early May.”

Fick said it is more common to knock those shrubs back with herbicides. “We ought to be able to do a pretty good job on all three of these species in June,” he said.

K-State’s most updated recommendations for using herbicides to manage pastures are available in the 2019 Chemical Weed Control for Field Crops, Pasture, Rangeland and Noncropland.

Fick noted that it takes planning to get the right herbicides for the particular species that is in a field. For example, the common herbicide 2,4-D is available in many products and can be very effective against buckbrush.

K-State research, though, has shown that other herbicides may work just as well, and in fact, mixing 2,4-D with other products is sometimes the most effective way to get long-term control.

Roughleaf dogwood can be the most difficult to control of the three, so K-State’s trials serve as a good guide for pasture managers.

“One of the better products we’ve found (to control roughleaf dogwood) is PastureGuard HL,” Fick said. “When we treat individual clumps, we’ve seen a 50 percent mortality rate or better. Dogwood is a tough one to kill.”

Fick said a more effective approach to control roughleaf dogwood is using Surmount or 2,4-D plus the herbicides picloram and triclopyr.

K-State’s publication also includes guidelines for using ground pellets and other management strategies.

Fick published his recommendations for controlling woody brush species in the K-State Department of Agronomy’s weekly e-Update, available at agronomy.ksu.edu. Those needing assistance or who have questions may also contact their local extension agent.

Source: Kansas State University extension