How to Control Weeds in your Switchgrass
Regardless the planting method performed, several requirements must be met in order to have a successful stand of switchgrass. Previous to planting and during the establishment year, weed control is essential for a productive stand. Because SG is slow to germinate and top growth is minimal the first year, weed control is imperative. Lack of weed control is the number one reason for stand failure. Weed control on newly established SG stands can be accomplished by mowing and or herbicides. There are several herbicide options and new alternatives are being explored. Herbicides may be either pre emergence or post emergence and several can be used as both.
Frequent mowing is also an option for weed control. The goal is to prevent the annual weeds from shading the native plants. Mow early and mow often, up to 6 times the first year if need be. Usually a good rule of thumb is June 1, July 1 and August 1, or when weeds are about 6 inches ahead of the SG. If frequent mowing is done, there is less likelihood of smothering the young native grass with a blanket of dead thatch. Herbicide treatments for weed control will generally produce a more vigorous stand of SG quicker than mowing alone. The most aggressive weed control will generally require both methods.