Johnsongrass is not a common weed in turf situations. It is frequently found on roadsides, but is also found in pastures and disturbed fields. It does not grow well in frequent, close mowing situations. As an adult plant, johnsongrass is characterized by its dense growth habit, with stems that can reach 6 ft in height. The leaf blades are rough, and the prominent white raised midveins that run the length of the leaf are distinctive. The seedhead is purple.
Perennial grass weeds are not desirable as turfgrass species under any conditions. Therefore, every effort should be made to prevent these weedy grasses from becoming established in turf, as selective control measures are usually difficult. Selection of adapted turfgrass species and cultivars and the use of cultural practices are important in minimizing weedy grass encroachment and competition. Management practices include (1) mowing at the recommended height for the selected turfgrass and removing clippings when seedheads of grassy weeds are present; (2) applying the proper amount of nitrogen at the correct time according to the turfgrass present; and (3) using soil tests to determine needed nutrients and lime.
panicle; seedhead is often purplish
membranous; fine hairs
Growth Season/Life Cycle
Leaf blade tip shape
Leaf blade width
0.4 - 1.2 inches (10 to 30 mm) wide
round to somewhat flattened