Johnson Grass, an upright perennial grass, growing to 6-8 feet tall and reproducing by rhizomes and seeds, is well adapted to compete with crop plants. Johnson Grass has some nutritional value but may become toxic to livestock when drought or frost happens during the growing cycle. A mature plant can produce over 80,000 seeds and more than 212 feet of rhizomes. Seeds may remain viable for up to 25 years.
Johnson Grass is one of the most costly weeds with which farmers must contend. It costs them millions of dollars each year in lost crops, poor quality grain and lower crop yields.
There are no approved biological controls for this weed. Cultivation at least every 3 weeks to a depth of 3-5 inches is an accepted method of control. Chemical control is available from a variety of herbicides.
Recommended herbicides are available at the Pratt County Noxious Weed Department on a cost-share basis.