Stems are pink to rusty red near the base. Panicles are large, loosely branched, purplish, and hairy.
Spikelets occur in pairs or threes and each has a conspicuous awn.
Johnson grass should be accurately identified before attempting any control measures. If identification of the species is in doubt, the plant's identity should be confirmed by a knowledgeable individual and by consulting appropriate books. It is widely distributed in tropical America, and is common in the southern U.S. Heavy infestations are found in all the major river bottoms of Missouri, with more than 300,000 acres infested in the Missouri Bootheel alone. It thrives in open, disturbed, rich, bottom ground, particularly in cultivated fields. Heavy river-bottom infestations can reduce corn or soybean yields in Missouri to a few bushels per acre.