Stem

  • Up to 8 ft. tall; many tillers arise from crown; stems slightly flattened with prominent nodes
Photo of green johnsongrass stem
 

Leaves

  • Up to 2 ft. long, 0.25-0.75 in. wide, white midvein and mostly hairless except near collar; ligule is membranous and tipped with fine hairs; NO auricles
Photo of johnsongrass adult plant growing outside
 

Flower

  • Seedhead open and pyramid-shaped; purplish-brown at maturity 
  • Seed is narrow, less than 0.25 in. long and reddish-brown to black 
Photo of dark brown and tan colored johnsongrass seeds
Photo of Johnsongrass seeds

Root

  • Deep, fibrous root system; rhizomes are white and fleshy with brown to purple nodes; roots and new plants often form at nodes 
Photo of green johnsongrass plant

Other

  • Grows best in moist soils; often found in crop fields, pastures, fencerows, roadsides, and along waterways; known to occur in Clark, Lincoln, and Lyon counties
  • Perennial; reproduces by seed and rhizomes; seedlings resemble corn and can best be identified by pulling a plant and examining the roots for an attached seed
  • Plants can be toxic to livestock after frost or drought
 

Control

  • Frequent mowing or tillage is effective; burning is NOT
  • Apply fenoxaprop, fluazifop, or sethoxydim to actively growing plants before boot stage; glyphosate, imazapic, or imazapyr between boot and bloom stages
Blecker, L., Creech, E., Dick, J., Gephart, S., Hefner, M., Kratsch, H., Moe, A., Schultz, B. 2020, Nevada Noxious Weed Field Guide – Johnsongrass, Extension, University of Nevada, Reno, Field Guide

Learn more about the author(s)

Heidi Kratsch
Heidi Kratsch
 

Also of Interest:

 
Needs Assessment for Noxious Weeds in Churchill County: Part 4 of 5 - Criteria for Herbicide Use and Selection
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 Davison, J., Powell, P., Schultz, B., and Singletary, L. 2012, University of Nevada Cooperative Extension
Nevada’s Priority Agricultural Weeds: Hoary Cress
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 B. Schultz, S. Foster 2021, Extension, University of Nevada, Reno, SP-21-03
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African mustard is a noxious weed that has been identified by the state of Nevada to be harmful to agriculture, the general public, or the environment. Learn more about this weed.
 Blecker, L., Creech, E., Dick, J., Gephart, S., Hefner, M., H. Kratsch, Moe, A., Schultz, B. 2020, Extension, University of Nevada, Reno, Field Guide
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Nevada Noxious Weed Field Guide – Common crupina
Common crupina is a noxious weed that has been identified by the state of Nevada to be harmful to agriculture, the general public, or the environment. Learn more about this weed.
 Blecker, L., Creech, E., Dick, J., Gephart, S., Hefner, M., Kratsch, H., Moe, A., Schultz, B. 2020, Extension, University of Nevada, Reno, Field Guide
Photo of Common St. Johnswort plant
Nevada Noxious Weed Field Guide – Common St. Johnswort
Common St. Johnswort is a noxious weed that has been identified by the state of Nevada to be harmful to agriculture, the general public, or the environment. Learn more about this weed.
 Blecker, L., Creech, E., Dick, J., Gephart, S., Hefner, M., Kratsch, H., Moe, A., Schultz, B. 2020, Extension, University of Nevada, Reno, Field Guide
 

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