🌿 Weed
ANX-WEED-0000254
Johnsongrass
Sorghum halepense
Johnsongrass (Sorghum halepense), a perennial grass weed of the Poaceae family.
- Family
- Poaceae
- Growth habit
- Grass
- Life cycle
- Perennial
- Invasive status
- Noxious/regulated weed in many countries
- Native region
- Mediterranean region, now naturalized on most continents.
- Reproduction
- Seed and thick underground rhizomes - a single plant can produce an extensive rhizome network in one season.
Environment
Habitat & Growing Conditions
- Habitat
- Cultivated fields, floodplains, roadsides, ditches.
- Climate requirements
- Warm temperate to subtropical; thrives in hot summers.
- Soil types
- Prefers fertile, moist soils but tolerates a wide range of conditions.
Impact
Crops Affected & Economic Impact
- Affected crops
- Maize, sorghum (cross-pollinates with and can reduce grain sorghum purity), soybean, cotton
- Competition impact
- Rhizome mats compete intensely for water and nutrients; young growth and drought-stressed plants can also be toxic to livestock (cyanogenic glycosides).
- Economic impact
- Listed as one of the world's ten worst weeds by the FAO due to its impact on row-crop yields.
Management
Control Methods
- Control methods
- Deep tillage to expose rhizomes, crop rotation with competitive smother crops, and preventing seed set.
- Organic control
- Repeated cultivation through the growing season to exhaust rhizome reserves; mowing before seed heads form.
- Chemical control
- Systemic herbicides (e.g. glyphosate) for rhizome kill; selective grass herbicides in broadleaf crops. Resistant populations are documented in several countries.