Cogongrass in Hillsborough County

I received a call last week from a landowner who is concerned about the spreading of cogongrass in Hillsborough County.  His concerns are justified considering this invasive grass chokes out natural habitat, creates a fire threat along roadsides, and is costly to control if it becomes established in border areas or pastures.  I also see areas where this grass is taking over the right-of-ways and starting in pastures or home sites with little effort to stop it.  This could create a long and costly battle down the road.

For controlling this invasive weed, only active ingredients glyphosate and imazapyr are suitable as control agents but their use can effect wanted vegetation nearby.  Control will also take a while if only sprays are used, as the rihizomes can resprout and produce new plants in a ring around the edges of where the spraying was done.  Usually multiple sprays over a few years are needed for control.  Think about three years for proper control.  When possible discing or tilling to break the rhizome chains to induce sprouting will help form new sprouts that can be sprayed. 

Here is an article on cogongrass control from the Journal of Invasive Plant Science Management on a study using glyphosate, imazapyr, or the combination at different timings and how control can be achieved in three years. https://www.srs.fs.usda.gov/pubs/47330    Here is a factsheet on controlling cogongrass in the nursery.  http://hillsborough.ifas.ufl.edu/documents/pdf/agriculture/ornamental_production/CogongrassPlantNurseries.pdf