Para grass
Native to: Africa
Introduced to the US as a forage, para grass has escaped cultivation and is established throughout several southern regions of the country. It has been intentionally introduced in some places as a “ponded pasture grass” due to its capability to establish on poorly drained (swampy or seasonally waterlogged) soils as well on free-draining soils in high rainfall environments. This species is considered one of the world’s worst weeds in the United States, Australia, Mexico, and Central America.
Family: Poaceae
Habit: perennial grass, stems will often root at the base, and can reach up to 8 feet in height, having hairy nodes and sheaths.
Leaves: Leaf blades are 4 to 12 inches long and ½ an inch wide.
Flowers: panicle is up to 12 inches long, with numerous spreading branches.
Spikelets: roughly 0.12 inches long, elliptic, with a purplish rachis.
Distribution in Florida: South, Central, and into the Northeast
Para grass spreads via creeping stolons, cuttings, and seed. It forms floating mats in drainage ditches or irrigation canals, resulting in the impediment of water flow. This impediment on water flow can also restrict navigation of water vessels in shallow water and prevent recreational use of waterways. Aggressive in nature, para grass can form large monocultures through fast growth and high productivity crowding out native plants. para grass is even thought to have allelopathic activity on other plants, ensuring its success.
Do not allow seed set to occur. Prevent movement of plant material from into uninfested areas by cleaning boats, equipment, and gear.
Cattle grazing on para grass seems to keep this invasive in check and is used extensively by many producers as a forage. However, education on the problems associated with para grass should be used to prevent unwanted infestations. Burning can be very useful in removing excess biomass, allowing for more effective chemical control.
Small infestations can be removed with repeated, aggressive tillage.
Grass carp will eat it, but research has shown the fish provide partial control.
Foliar applications of glyphosate at 3–4 quarts per acre or imazapyr (Arsenal, Habitat) at 2–3 quarts per acre. Spot treatments containing 3% glyphosate or 0.5–1% imazapyr are effective. A more selective option is TIGR, which can be broadcast at 40 oz/A or applied as a spot treatment at 3–5%. Re-treatments will be required with TIGR to maintain control. Consult your local UF IFAS Extension for further assistance with management recommendations. Additional information can be found in the EDIS Publication Integrated Management of Non-Native Plants in Natural Areas of Florida.
UF IFAS Assessment of Non-Native Plants in Florida’s Natural Areas
View records and images from University of Florida Herbarium