Regardless of the cause, johnsongrass is difficult to control. Basically there are only two options unless you plan to kill everything in the field and start over.
The first option is to let cattle “graze it out.” If the field is fenced or you can put up a temporary fence, put cattle on the field after the first hay cutting and leave them on it throughout the summer. Following this practice for two years in a row will greatly reduce, if not totally eliminate johnsongrass from the field. Johnsongrass cannot tolerate continuous grazing during the summer.
The other option is to use a high rate of a non-selective herbicide, like Round-up, in a rope-wick applicator. Once johnsongrass gets up about two to three feet tall, use the rope-wick to apply the herbicide to only the tall grass. Johnsongrass grows much faster and taller than most other grasses which allows the rope-wick applicator to only contact the johnsongrass and not touch the shorter grasses like fescue and orchardgrass.
Of course, johnsongrass is currently dormant and there is not anything we can do to it at this time. But if you had problems with johnsongrass last summer you should start making plans now if you want to get rid of it. For more information, call the Extension Office at 706-638-2548.
Norman Edwards is coordinator of Walker County Extension Service.