Johnson Grass • Sorghum halepense
Conditions: Allergic rhinitis; allergic asthma; allergic conjunctivitis.
Symptoms: Itchy, stuffy, or runny nose; post-nasal drip; sneezing; itchy, red or watery eyes; asthmatic symptoms.
Physical description: Grows between 2-7 feet tall, long, broadleaf blades; flower head is large, open, well-branched, dark reddish, or purplish-brown.
Environmental factors: Very common; found in fields, crops (usually corn), roadsides, and sandy, rugged areas; reproduces by seeds; grass pollen grains travel hundreds of miles.
Cross-reactivity: Bahia grass; figs; maize pollen; melons; oranges; tomatoes.
Included species: Andropogon halepensis, holcus halepensis, sorghum miliaceum.
- “Johnsongrass (Sorghum halepense).”Weed Gallery: Johnsongrass–UC IPM. http://ipm.ucanr.edu/PMG/WEEDS/johnsongrass.html
- “Plants – Johnsongrass (Sorghum halepense).”
National Invasive Species Information Center. https://www.invasivespeciesinfo.gov/plants/johnsongrass.shtml
- “Johnsongrass.”Merriam-Webster. https://www.merriam-webster.com/dictionary/johnsongrass
Did You Know?
Johnson grass was brought to the United States in the 1800s as a forage crop. Today it is considered among the world’s 10 worst weeds because of its invasive nature.