Johnsongrass
Sorghum halepense · Warm-season, Perennial, C4 grass
AI-generated identification · may be incorrect
Grass Category
Invasive/Weed Grass, Pasture/Forage Grass
Hardiness Zones
Thrives in USDA Hardiness Zones 6 through 10. Exhibits good heat tolerance and goes dormant with winter frost, surviving as underground rhizomes
Grass Family
Poaceae, subfamily Panicoideae, tribe Andropogoneae
Variety / Cultivar
Wild type (No specific cultivated varieties commonly managed as turf)
About This Grass
A tall, coarse perennial grass growing anywhere from 3 to 8 feet high when mature. It features stout, erect stems, broad bright green leaves often with a distinct white midrib, and large, open, purplish panicle seed heads.
Blade Characteristics
Coarse blades, typically 0.5 to 1.5 inches wide, flat shape with a pointed tip, bright green color with a prominent white midvein. Vernation is rolled in the bud. Features a membranous ligule that is jagged or fringed with hairs, and lacks auricles
Root System
Deep, aggressive, and extensive fibrous root system combined with thick, fleshy, white rhizomes that store nutrients. Fast establishment from seeds and rhizomes, moderate to high drought tolerance once established, and forms persistent patches
Growing Information
Origin Region
Native to the Mediterranean region and parts of Asia; now widely naturalized and often considered a noxious weed globally in tropical, subtropical, and warm temperate regions
Growth Habit
Aggressive rhizomatous and bunch-type growth habit, spreading rapidly via extensive, thick underground rhizomes and copious seed production to form dense patches
Sunlight & Water Needs
Requires full sun for optimal growth. Moderate water needs, highly drought-tolerant once established due to deep roots and rhizomes. Prefers fertile, well-drained soils but adapts to a wide range of soil pH and types
Mowing & Maintenance
High maintenance if attempting eradication, as frequent low mowing can weaken it but rarely kills established rhizomes. Generally managed as a weed in lawns and agricultural fields requiring targeted herbicides or repeated pulling
Special Characteristics
High weed invasiveness, can produce toxic cyanogenic glycosides (prussic acid) under drought or frost stress when grazed by livestock. Difficult to control due to extensive rhizome network and high seed viability
Ecological Information
Introduced species in North America, often highly invasive and outcompetes native vegetation. Provides limited cover for some wildlife, but its aggressive nature disrupts native ecosystems and agricultural productivity