Scientific Name: Sorghum halepense

Common Name: Johnsongrass

Synonyms: Holcus halepensis, Sorghum miliaceum

Habit: Johnsongrass is a course, generally clumping grass, and one of the most troublesome perennial grasses in the U.S. Growth is surged by thick aggressive rhizomes and flowering last from June to July.

Leaves: The plant can grow 6 to 7 ft height. It has a fringed membranous ligule (2.0-5.5mm long). Leaf blades are 20 to 60 cm long and 10-30 mm wide at maturity and have a thick white midvein. The leaf blade and sheath are hairless beside a few sparse hairs near the collar.

Identifying Characteristics: Johnsongrass can spread through seed or rhizomes.

Flower Seed Head: The seedhead flowers May through October. The seedhead is an open panicle (12-50 cm long) with numerous branches and has an overall pyramid outline. The seedhead starts out green but by maturity it turns dark reddish or purple brown.

Seed Fruit: The seed is produced on the shorter floret which is 4-5.5 mm long. The seed itself is oval shaped, long dark reddish brown(3-5mm long).

Where Found: Johnsongrass prefers rich soils and doesn't tolerate close mowing. It grows in cultivated, reduced-tillage, and perennial cops.

  • Life cycle: perennial

  • Plant type: Grass

  • Auricle: not present

  • Plant family: Poaceae

  • Leaf arrangement: rolled in bud

  • Hair surface: no hairs

  • Ligule: membrane

  • Length: more than 3 mm; 2-3 mm

  • Seed head: panicle

  • Width: more than 15 mm

  • Grass stem: round