Sorghum halepense (Johnsongrass)
Sorghum halepense · Warm-season, Perennial, C4 grass
Grass Family
Poaceae, subfamily Panicoideae, tribe Andropogoneae
Grass Category
Invasive/Weed Grass, occasionally used for Pasture/Forage but generally considered a noxious weed
Variety / Cultivar
None (wild species)
Hardiness Zones
USDA Zones 6-11; dies back to the ground in winter but rhizomes survive deep freezes.
About This Grass
A coarse, tall-growing perennial that can reach 3-8 feet. It has distinctive reddish-purple to bronze open panicle seed heads (visible in foreground). Foliage is bright green and becomes very dense if left unmowed.
Blade Characteristics
Coarse width (up to 2 cm), flat shape with a prominent white midrib, pointed tips. Vernation is rolled; ligule is membranous and usually fringed with fine hairs; auricles are absent.
Root System
Extensive, thick, creeping scaly rhizomes that store energy; very deep fibrous roots; high thatch and sod-forming capability making it extremely difficult to eradicate.
Growing Information
Origin Region
Native to the Mediterranean region; widely naturalized in the United States, especially in the South and Midwest transition zones.
Growth Habit
Rhizomatous (aggressive underground spreading) and prolific seed producer; forms dense, competitive colonies.
Sunlight & Water Needs
Full sun preferred; high drought tolerance once established; thrives in rich, moist soils but survives in many conditions (pH 5.0 to 7.5).
Mowing & Maintenance
Not typically mowed for turf; if in pasture, maintain 6-10 inches. Requires high maintenance for control/eradication due to chemical resistance and rhizome survival.
Special Characteristics
Extremely high wear tolerance; invasive; drought-hardy; notably toxic to livestock (prussic acid/cyanide poisoning) after frost or drought stress.
Ecological Information
Introduced/Invasive status in most of North America; outcompetes native prairie species; provides some cover for small birds but generally degrades local biodiversity.