Torpedo grass (Panicum repens) is a scourge in our area. It is not only difficult to control in lawns, it is nearly impossible to control. It is a seriously fast-growing, invasive species that must be continually managed in the lawn in order to keep it suppressed.
Native to Africa and/or Asia, it was introduced to the United States before 1876, primarily through seed used for forage crops. But what really did it was when the U. S. Department of Agriculture imported and distributed torpedo grass seed in the early 1900s for planting in pasturelands. This was to provide forage for cattle. Ironically, it proved inferior for use as a forage crop. Now it is found in the Gulf South from Florida to Texas and along tropical and subtropical coasts around the world.
The name comes from the hard, sharp point on the rhizome that runs horizontally underground, like a torpedo going through the water. The rhizomes can travel a foot or more deep, and the hard points are able to punch through landscape fabric and weed barriers.
Even if introduced into a small area, this weed can rapidly spread to become a major problem. Torpedo grass spreads vigorously vegetatively – growing stolons a foot or so underground rapidly in all directions. If it is nearby, it can show up in a lawn seemingly overnight. It can begin growing from even a tiny piece of its root system, so it is often moved from place to place in soil that is imported to an area. This is another reason torpedo grass is so difficult to control even when pulled up – because if even a tiny piece of its extensive root system is missed, it will continue to replenish itself.
In established lawns, the use of herbicides only achieves control of torpedo grass with diligent, repeated treatments that are spaced at least two weeks apart. Care must be taken to choose the correct selective herbicide for the grass type, as damage and even grass death can occur if the wrong product is used. Even with this diligent, repeated treatments, the goal for torpedo grass control is not to eradicate it, but to prevent it from taking over and killing the existing grass. And it can eventually cause the death of the existing grass in a lawn. Studies have shown that torpedo grass exudes phytotoxic chemicals, which are harmful to competing vegetation, a phenomenon known as allelopathy.
Torpedo grass is a TERRIBLE WEED! It is widespread in our area, and due to its aggressive, fast-growing nature, its presence in a lawn means that it cannot be controlled with a regular lawn care program from Sexton Lawn and Landscape. The reason for this is the timing – lawn care applications are spaced at 4 to 8 weeks apart. We will spray torpedo grass at a regular lawn care visit, but this will not even make a dent in the growth rate of this noxious weed.
Sexton Lawn and Landscape recommends a torpedo grass management program to supplement a regular lawn care program when torpedo grass is present in a lawn. This will keep torpedo grass suppressed, giving the desirable turf a better chance of thriving! The program consists of extra herbicide treatments with the correct selective herbicide at two-week intervals. The price for these programs starts at $45.00 for each visit.