Brachiaria mutica, also known as Urochloa mutica, is an invasive grass species native to Africa. In its native lands, Brachiaria is cultivated as a forage grass and was brought to the U.S for this purpose. In areas where para grass is not grazed on by cattle, it has become a serious weed. Upon its introduction to the U.S., naturalization of para grass has occurred throughout several southern regions of the country, including Florida, in cultivated and disturbed areas. para grass is able grow in canals and low, wet areas, displacing native vegetation in marshes and swamps. Florida’s Exotic Pest Plant Council has listed Brachiaria mutica as a Category 1 invasive plant in Central and Southern Florida because of these invasive characteristics.
Para grass is in the family Poaceae, along with other familiar grasses such as St. Augustinegrass, bermudagrass, centipedegrass and many ornamental grass species. A perennial species, para grass spreads via creeping stolons, cuttings, and seed. Stems will often root at the base, and can reach up to 8 feet in height, having hairy nodes and sheaths. Leaf blades are 4 to 12 inches long and ½ an inch wide. The panicle is up to 12 inches long, with numerous spreading branches. Spikelets are roughly 0.12 inches long, elliptic, with a purplish rachis. Although there are many flower heads produced by para grass, seed production is very poor with poor seeds viability.
Para grass can form 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. para grass is even thought to have allelopathic activity on other plants, ensuring its success. In 1986 para grass was found in 207 public water bodies in Florida. Through control and management efforts, this number dropped in 1994 to 183.
Do not allow seed set to occur and prevent movement of plant material from into uninfested areas.
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.
Small infestations can be removed with repeated, aggressive tillage. Burning can be very useful in removing excess biomass, allowing for more effective chemical control.
There are no known biological control agents for para grass.
For broadcast applications to larger areas, glyphosate at 2 to 4 lbs-ai/acre can be used. Imazapyr can also be very effective at 0.5 to 1 lbs-ai/acre, but adhere strictly to irrigation restricts on the label (Habitat) if applied near water. Imazapyr can also cause non-target damage due to soil residual properties. Always use a good surfactant at 0.25% with imazapyr and with certain glyphosate formulations.