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Johnsongrass (Sorghum halepense) is an aggressive perennial common in agronomic fields, along roadways and waterways, and in low lying areas prone to flooding. Mature leaf blades are 5 to 20 inches long with an obvious white rib down the middle. Plants reproduce by seed and perennial rhizomes, making control difficult. Rhizomes are stout compared to other grasses. 

Johnsongrass foliage and stems (Evans, University of Illinois, foliage and stems.

(Photo: Chris Evans, University of Illinois,

Johnsongrass growth habit (Miller and Bodner, Southern Weed Science Society, growth habit.

(Photo: James H. Miller and Ted Bodner, Southern Weed

Science Society,



  • Apply pre-emergent herbicides to help prevent seedling establishment. 
  • Post-emergent herbicides selective for grasses can be applied when plants are seedlings, but these are less effective once rhizomes have formed.
  • Avoid cultivation, which spreads plants.


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