Grasses

Grasses
Arabiangrass
Buffelgrass
Cheatgrass
Crimson fountaingrass
Field sandbur
Giant reed
Japanese brome
Johnsongrass
Jointed goatgrass
Lehmann lovegrass
Mediterranean grass
Quackgrass
Ravennagrass
Red brome
Rescuegrass
Ripgut brome
Southern sandbur
Tall fescue
Uruguayan pomps grass
Weeping lovegrass
Wild oat

 

Johnsongrass
Sorghum halepense (L.) Pers. (Grass family, Poaceae)
 

Description

Johnsongrass is a large, coarse, introduced, warm-season, perennial bunchgrass growing to 6-1/2 feet in height, with reddish to purplish- black panicles; plant produces vigorous rhizomes.

Plants: Seedlings resemble young corn seedlings; mature plants typically tufted, culms 1-3/4 to 6-1/2 feet tall and 1/8 to 3/4 inch thick; nodes appressed pubescent; internodes glabrous; collars broad, whitish or pale green, smooth; auricles lacking; sheaths open, ribbed, compressed, glabrous or sparsely hairy near blade junction, shorter than internodes, pale green to reddish; ligules l-1/6 to 1/4 inches long, membranous, conspicuously ciliate; leaf blades, flat, 4 to 35-1/2 inches long and 3/8 to 1-9/16 inches wide.

Inflorescence/Spikelet/Floret: Flowers May to October; panicles 4 to 16 inches long, 2 to 10 inches wide, primary branches compound, terminating in groups of 1 to 5 spikelet pairs; disarticulation usually beneath the sessile spikelets, sometimes also beneath the pedicelled spikelets; sessile spikelets 3/16 to 1/2 inch long and less than 1/8 inch wide; calluses blunt; glumes hard, shiny, appressed pubescent; upper lemmas unawned, or with a geniculate, twisted awn to 1/2 inch; pedicelled spikelets, 1/8 to 1/4 inch long; glumes membranous to leathery, unawned; each fertilized sessile spikelet produces a single grain.

Habitat

Cultivated and disturbed or degraded moist sites in meadow, grassland, and woodland communities, and roadsides within elevations that generally range below 8,000 feet.

Propagation/Phenology

Reproduces primarily by fast-growing rhizomes that produce new plants; one plant can produce up to 295 feet of rhizomes in a single season.

Comments

Native to the Mediterranean region; Johnsongrass grows rapidly, is highly competitive, and can be difficult to control; plants can rapidly develop colonies.This species generally occurs as a weed in wildland areas of the Southwestern Region rather than as an invasive plant.

collage of imaage of johnsongrass

 

 
Forest Service Shield
Invasive plants and weeds of the national forests and grasslands in the southwestern region
Ariabiangrass inflorescence Arabiangrass spikelet Arabiangrass plants Johnsongrass inflorescence Johnsongrass spikelets Johnsongrass plants johnsongrass leaf-collar region