Johnsongrass
Family Poaceae
Sorghum halapense
Designation/Status
Arizona Noxious Weed List - Not Listed
Federal Noxious Weed List – Not Listed
Origins
Johnsongrass is native to the
Mediterranean region.
Plant Characteristics
Life Cycle: Spreads by seed and
by a very extensive rhizome. Seeds dispersed by wind, water,
wildlife (especially birds), livestock, and contaminated crops,
vehicles, and machinery. Up to 80,000 seeds and 8 kg of rhizomes
can be produced by one plant in one growing season.
Visual Appearance: Coarse
perennial grass. Stalks reaching from 1.5 to over 6.5 feet tall.
Long, bright green leaves provide a very leafy appearance.
Inflorescences are purplish.
Habitat
Grows primarily in disturbed
areas such as cultivated fields, along irrigation canals,
bottomlands, and open ground. Adapted to a wide range of soil
types, but prefers porous, fertile soils and thrives in warm,
subtropical, humid environments with summer rainfall
Control Measures
Mechanical and Cultural:
Manual removal of the entire plant,
including the deep rhizomous root, is recommended. Mowing, heavy
grazing, repeated tilling and plowing have also proved to be
effective control measures.
Biological: None
Chemical: Systemic
herbicides applied while the plant is actively growing are
typically the most effective chemical control measure.
Other Points of interest
Johnsongrass is now common throughout the warmer parts of the
world. First appeared in the
southern states before 1840 under many names, including "Guinea
grass", "Means grass", and "bankruptcy grass". Documented in
Arizona in 1890. Was introduced as a hay or forage crop.
