Practical information to identify and manage non-native, invasive plants
The Quiet Invasion:A Guide to Invasive Plants of the Galveston Bay Area
Sorghum halepense
| USDA Symbol: | SOHA |
| ITIS TSN: | 42111 |
| Presence: | Current Invaders |
| Habitat: | Terrestrial |
| Native Range: | Mediterranean region of Europe and Asia |
Toxic Characteristics
Produces a rapidly acting poison called hydrocyanic acid which is toxic to livestock if ingested. May also accumulate dangerous levels of nitrates after nitrogen fertilization or during drought.Geographic Distribution
Located in nearly every state of the U.S., with the exception of some northern states. Located in all regions of Texas, including Harris, Brazoria, and Galveston counties of the lower Galveston Bay watershed.Introduction Pathways
Brought to South Carolina in the early 1800s as a forage crop. Continues to spread by seed dispersal in agricultural machinery.Specific Primary Habitats
Tolerates a wide variety of situations, but prefers full sun and disturbed pasture, roadsides, ditches, and waste areas. Highly favors overgrown abandoned yards and lots.Identifying Characteristics
Noted by its erect culms and the presence of small hairs at leaf nodes. Leaf sheaths are without hairs. Leaf blades are very long and 1/4 - 1/2 in. wide. The inflorescence occurs terminally as a long panicle (6 - 10 in. long), that when mature, is marked by its purplish-red color and opened branches extending radially outward. When immature, inflorescence will appear as a single stalk with branches folded upwards. Seeds are small and enclosed in spikelets.Reproduction Characteristics
Sprouting from rhizomes causes on-site spread, but is also a prolific producer of long-lived seeds. Flowering usually begins in April, roughly 2 months after germination. Seeds usually sprout the following growing season.Growth Characteristics
Reaches 6 feet in height and forms coarse extensive rhizomes, which store energy for rapid growth the following season. Individual plants may produce 180 - 270 feet of rhizomes in a growing season.Ecological, Economic, or Social Impact
Johnsongrass forms monospecific stands, reducing native species diversity. Impacts agriculture by introducing diseases to crops while also competing for nutrients. Poses a fire risk during dry periods, and is a known allergenic.Suggested Control Methods
Plant slashing or mowing is recommended as flowering begins, before seed set. Glyphosate application is most effective when plants are greater than 18 inches tall and have a blooming inflorescence. In this case, remove inflorescences to prevent seed set.|
Native Species Alternatives
Below is a list of alternative plants that are native to the area:
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Lists
This species belongs to the following lists:
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Images
To view a larger version of an image, click on the thumbnail. Cluster of Johnson grass; note broad leaves and reddish seed head. Photo courtesy of Ted Bodner, Southern Weed Science Society, www.forestryimages.org; Image Number 1120381. |
 Close-up of broad, long, leaves and seed head of Johnson grass. Photo courtesy of Ted Bodner, Southern Weed Science Society, www.forestryimages.org; Image Number 1120382. |
 Close-up of seed head of Johnson grass. Photo courtesy of James H. Miller, USDA Forest Service, www.forestryimages.org; Image Number 1120383. |
 A Johnson grass infestation in a soybean field. Photo courtesy of Charles T. Bryson, USDA Agricultural Research Service, www.forestryimages.org; Image Number 1299122. |
 Large infestation of Johnson grass in an open clearing. Photo courtesy of David J. Moorhead, The University of Georgia, www.forestryimages.org; Image Number 2308021. |