Identifying Noxious Weeds of Ohio

Bulletin 866-98

Johnsongrass (Sorghum halepense)

Habitat: rich soils, cultivated fields throughout Ohio

Life cycle: perennial, spreading by rhizomes and seed

Growth Habit: 3-6 feet or more

Leaves: 0.5 -1 inch wide, smooth blades with a prominent white midvein

Inflorescence: July - October. Can be up to 1 foot or more in length; panicles are loosely branched, purplish, and hairy. spikelets occur in pairs or threes

Roots: Fibrous. Rhizomes are found close to the soil surface. They are stout with purple spots and scales at the nodes.

Stem: smooth, pink to rusty red near the base

Similar plants: Look for rhizomes to distinguish johnsongrass from shattercane (Senecio bicolor).

The problem is.... johnsongrass is very competitive with crops, spreading rapidly by rhizomes. It was initially introduced to the US as a forage crop, but its aggressive growing habit quickly made it undesirable. It is listed as a noxious weed in numerous states.

The rhizomes of johnsongrass help distinguish it from shattercane, and allow the plant to survive tillage.	Johnsongrass has established itself along the edges of this cultivated field.

Note the prominent white midveins on the leaves.