Sorghum halepense aka Johnsongrass

Sorghum halepense, also known as Johnson grass or Johnsongrass, is a coarse, herbaceous perennial grass in the grass family, Poaceae. It is native to Asia and northern Africa, but has been introduced to all continents except Antarctica, and most larger islands and archipelagos. The plant reproduces by rhizomes and seeds and can grow up to 7 feet tall. Although Johnson grass has been used for forage and to prevent erosion, it is often considered a weed due to its invasive nature. It grows and spreads rapidly, making it a threat to cash crops planted by farmers. It can be found in crop fields, pastures, abandoned fields, forest edges, and along streambanks, particularly in open, disturbed, rich bottom ground. Johnson grass can cause health problems for herbivores such as cattle and horses. The foliage can contain sufficient amounts of hydrogen cyanide to kill them if it is eaten in large quantities, and it can also cause 'bloat' in such herbivores from the accumulation of excessive nitrates. However, it is generally edible. Johnson grass is also considered to be one of the ten worst weeds in the world, and is listed as either a noxious or quarantined weed in 19 states in the United States. It has been found to be resistant to the common herbicide glyphosate in Argentina and the United States. The distinguishing characteristics of Sorghum halepense are the ribbed leaf sheath, the conspicuous midrib, the large, purplish panicle, and the extensive rhizome system. It is often confused with Panicum bulbosum, which can be recognized by its short, knotty rhizomes and bulbous swellings at the base of the culms. Sorghum halepense was named after an Alabama plantation owner, Colonel William Johnson, who sowed its seeds on river-bottom farm land circa 1840. The plant was already established in several US states a decade earlier, having been introduced as a prospective forage or accidentally as a seedlot contaminant. Fields of this grass fell into a "sod bound" state of insufficient new growth unless they were plowed every two or three seasons. A genetic study has confirmed that the weed was introduced to the US from Alabama and North Carolina, and detected an unreported independent introduction from Arizona. Fifty-three countries, ranging in latitude from 55 N to 45 S report Johnson grass as a major problem; the problem is most serious in the region from the Mediterranean to the Middle East and India, Australia, central South America, and the Gulf Coast of the United States. The 1889 book The Useful Native Plants of Australia records that Sorghum halepense is a "strong, erect-growing species, varying from two to ten feet high, succulent when young, a splendid grass for a cattle run, though not much sought after by sheep. It is a free seeder. The settlers on the banks of the Hawkesbury (New South Wales) look upon it as a recent importation, and seed of it has been distributed under the name of Panicum speciabile. (WooUs) Coast of Queensland, New South Wales, and Western Australia."