University of Missouri Extension

IPM1024, Revised October 2010

Identifying Grass Seedlings

Johnsongrass (Sorghum halepense)

Perennial grasses

Description

Johnsongrass is a noxious weed because of its invasive nature. It spreads quickly from its stout rhizomes to form dense colonies. Leaves are smooth on both surfaces, 8–25 mm wide and contain a prominent midvein. Auricles are absent, and the ligule is membranous. As the plant matures, a row of hairs may develop along the top of the ligule.

Mature johnsongrassMature johnsongrass.
 

Collar region SeedheadCollar region: membranous ligule.
Right, seedhead.
 

Habitat

Johnsongrass grows in nearly any soil, but it is most troublesome as an agronomic weed of row crops, in pastures and along rights-of-way.

Distribution

Johnsongrass is abundant in southern and western Missouri. In the United States, it can be found as far north as the southern New England states, Wisconsin and Michigan.

Similar species

Shattercane is closely related but is an annual. Johnsongrass is a perennial with stout underground rhizomes, which shattercane does not have. The seed of shattercane is much larger and rounder than those of johnsongrass. If seedlings are carefully removed from the soil, the seed may still be attached for identification.

IPM1024 Identifying Grass Seedlings | University of Missouri Extension

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