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

Stem

Up to 8 ft. tall; many tillers arise from crown; stems slightly flattened with prominent nodes

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

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

Learn more about the author(s)

Ashley Nickole Andrews

Also of Interest:


Nevada Noxious Weed Field Guide – Johnsongrass Johnsongrass 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

Nevada Noxious Weed Field Guide – Johnsongrass