For several years botanists and land managers have been on the lookout for Cogongrass (Imperata cylindrica) in southern Arkansas. This aggressive species, native to Southeast Asia, has rapidly spread across the Deep South over the past few decades and is considered one of the worst invasive species in the world, causing both economic and ecological damages that impact forestry, agriculture, rangeland, and natural ecosystems. It has now been documented from nearly every county in Florida, Alabama, and Mississippi. Until June 8 however, it wasn’t known from Arkansas. That’s when sharp-eyed retired U.S. Department of Agriculture Botanist Charles Bryson was driving through West Helena in a rainstorm. He thought he spied a patch along Highway 49 and notified Theo Witsell, Chief of Research for the Arkansas Natural Heritage Commission.
Pictured above -- Patch of Cogongrass (Imperata cylindrica), photo by Charles Bryson.
Witsell had worked with and exchanged specimens (including some of Cogongrass) with Bryson for years and knew that if anyone knew a patch of Cogongrass, even at 60 miles per hour in a rainstorm, it was Bryson. He immediately notified colleagues at the Arkansas Department of Agriculture Plant Industries Division (ADAPID) and Arkansas Department of Transportation (ArDOT) to let them know of the unfortunate find. A flurry of emails followed, briefing staff of several other agencies, and immediate plans were made for control and additional surveys.
Meanwhile, Bryson drove back through West Helena in fairer weather on June 13 and confirmed his earlier suspicions, documenting the occurrence with photographs and collecting herbarium specimens. On June 16, Paul Shell, Plant Inspection and Quarantine Program Manager with the ADAPID led a multi-agency team that included staff from the Forestry Division and U.S. Department of Agriculture Animal and Plant Health Inspection Service (APHIS) to spray the population with herbicide. ArDOT Botanist Joe Ledvina conducted surveys along Highway 49 and other roads in the area. Thankfully he did not detect any additional populations. The agencies are planning to conduct annual surveys along this and other routes coming into southeastern Arkansas from Mississippi. (Pictured at right, part of the team surveying for Cogongrass, photo by Aaron Gifford, Agriculture Specialist, Arkansas Department of Agriculture)
Cogongrass has bright green leaves with serrated margins and a distinctive white vein that is slightly off-center from the middle of the leaf. It has no true, aboveground stem and these leaves emerge directly from stout, creeping rhizomes (underground stems). Cogongrass spreads rapidly from these rhizomes to form distinctive, very dense, circular patches which expand in size every year and are capable of displacing all other species on the ground. It is also one of the few warm-season grasses that bloom immediately after coming out of winter dormancy. A fact sheet with more information and photos is available here. (Pictured at left -- Closeup of cogongrass, photo by Aaron Gifford, Agriculture Specialist, Arkansas Department of Agriculture)
Ornamental selections of Cogongrass are sold under the names “Japanese Bloodgrass” and “Red Baron,” but these are illegal to buy, sell, trade, or use in the landscape in Arkansas because they can revert back to the invasive, wild type of Cogongrass. Previous Arkansas reports of wild Cogongrass were based on misidentifications of other grasses that look superficially similar. The species most often mistaken for Cogongrass is Silver Bluestem (Bothriochloa laguroides subsp. torreyana), a native species with a similar seed head that is very common along highway roadsides, especially in gravel just off the pavement. However, this species forms a tight clump and doesn’t creep to form large circular patches.
If you believe you have found Cogongrass in Arkansas, contact Paul Shell, [email protected] (or 501.225.1598) at the Arkansas State Plant Board.
Pictured above -- Patch of Cogongrass (Imperata cylindrica), photo by Charles Bryson.
Witsell had worked with and exchanged specimens (including some of Cogongrass) with Bryson for years and knew that if anyone knew a patch of Cogongrass, even at 60 miles per hour in a rainstorm, it was Bryson. He immediately notified colleagues at the Arkansas Department of Agriculture Plant Industries Division (ADAPID) and Arkansas Department of Transportation (ArDOT) to let them know of the unfortunate find. A flurry of emails followed, briefing staff of several other agencies, and immediate plans were made for control and additional surveys.
Meanwhile, Bryson drove back through West Helena in fairer weather on June 13 and confirmed his earlier suspicions, documenting the occurrence with photographs and collecting herbarium specimens. On June 16, Paul Shell, Plant Inspection and Quarantine Program Manager with the ADAPID led a multi-agency team that included staff from the Forestry Division and U.S. Department of Agriculture Animal and Plant Health Inspection Service (APHIS) to spray the population with herbicide. ArDOT Botanist Joe Ledvina conducted surveys along Highway 49 and other roads in the area. Thankfully he did not detect any additional populations. The agencies are planning to conduct annual surveys along this and other routes coming into southeastern Arkansas from Mississippi. (Pictured at right, part of the team surveying for Cogongrass, photo by Aaron Gifford, Agriculture Specialist, Arkansas Department of Agriculture)
Cogongrass has bright green leaves with serrated margins and a distinctive white vein that is slightly off-center from the middle of the leaf. It has no true, aboveground stem and these leaves emerge directly from stout, creeping rhizomes (underground stems). Cogongrass spreads rapidly from these rhizomes to form distinctive, very dense, circular patches which expand in size every year and are capable of displacing all other species on the ground. It is also one of the few warm-season grasses that bloom immediately after coming out of winter dormancy. A fact sheet with more information and photos is available here. (Pictured at left -- Closeup of cogongrass, photo by Aaron Gifford, Agriculture Specialist, Arkansas Department of Agriculture)Ornamental selections of Cogongrass are sold under the names “Japanese Bloodgrass” and “Red Baron,” but these are illegal to buy, sell, trade, or use in the landscape in Arkansas because they can revert back to the invasive, wild type of Cogongrass. Previous Arkansas reports of wild Cogongrass were based on misidentifications of other grasses that look superficially similar. The species most often mistaken for Cogongrass is Silver Bluestem (Bothriochloa laguroides subsp. torreyana), a native species with a similar seed head that is very common along highway roadsides, especially in gravel just off the pavement. However, this species forms a tight clump and doesn’t creep to form large circular patches.
If you believe you have found Cogongrass in Arkansas, contact Paul Shell, [email protected] (or 501.225.1598) at the Arkansas State Plant Board.