Sawgrass (Cladium jamaicense) is a perennial sedge notoriously difficult to eradicate due to its biology. This tough plant is not a true grass but a member of the sedge family, characterized by a coarse, fibrous structure and an aggressive, extensive underground root system. Its tenacious nature is largely attributed to rhizomes, which allow it to spread and regrow readily. Successfully removing sawgrass requires a targeted, multi-step approach that accounts for the plant’s robust structure and reproductive strategy.
Understanding Sawgrass Growth and Habitat
The plant’s physical characteristics give it its common name, as its long, strap-like leaves have sharp, serrated margins that can easily cut skin and fabric. Sawgrass culms, or stems, are triangular, a feature that distinguishes it from true grasses, and they can grow up to 10 feet tall, forming dense, impenetrable stands. This species is native to the wetlands of the tropical Americas and thrives in freshwater and brackish marshes, pond edges, and damp, often calcareous soil.
The primary reason sawgrass is hard to control lies beneath the soil surface in its extensive rhizome network. This highly developed perennial system allows the plant to reproduce asexually, sending out new shoots from underground stems. Rhizomes are stout and extensive, making simple cutting of the leaves ineffective since the stored energy remains intact. Therefore, control methods must target the entire plant, not just the visible foliage.
Physical Removal Methods
For smaller infestations or in environments where chemical use is restricted, physical removal is a viable but highly labor-intensive option. The goal of this manual process must be the complete extraction of the rhizome and root ball, not just the above-ground growth. Using a garden spade or a sturdy fork after a soaking rain can help loosen the soil and allow for careful removal of the entire root system. You must pull up the roots completely, as any small segment of the rhizome left behind can sprout a new, full-sized plant.
Repeated cutting or mowing of the above-ground growth is a method of attrition that attempts to starve the underground rhizomes. This must be done frequently, preventing the plant from photosynthesizing and replenishing its energy reserves. Another non-chemical method involves smothering the sawgrass patch using sheet mulching or solarization. Covering the area with an opaque material, such as black plastic sheeting or thick cardboard, starves the plants of sunlight, killing them over time.
Solarization involves covering the area with clear plastic during the hottest months to superheat the top layer of soil, effectively cooking the plants and seeds. For both smothering and solarization, the sawgrass should be cut as short as possible before covering. These methods require patience, often taking several weeks to months to be fully effective in killing the stubborn underground rhizomes. For the smothering method to be successful against a tenacious plant like sawgrass, the barrier must be thick enough to prevent the sharp rhizome tips from piercing through the material.
Selecting Appropriate Herbicides
Chemical control is often the most efficient method for large or widespread sawgrass infestations. Herbicides containing the active ingredient glyphosate are effective against this tough sedge. Because sawgrass grows primarily in wetland or aquatic environments, it is necessary to use a glyphosate formulation specifically approved for aquatic use, such as Rodeo or Accord Concentrate.
Standard, non-aquatic glyphosate products contain surfactants that are toxic to aquatic organisms like fish and amphibians. Aquatic-approved formulations use a safer surfactant or require the user to mix in an aquatic-safe surfactant separately. The herbicide should be applied as a foliar spray directly to the leaves of actively growing plants to maximize uptake and translocation down to the rhizomes.
Timing the application is a major factor in the chemical’s success, with the best results occurring when the plant is vigorously growing and actively moving nutrients to its roots. This is typically during the late spring or summer months. Always wear personal protective equipment (PPE), such as gloves and protective eyewear, and meticulously follow all instructions and concentration limits on the product label. Avoiding spray drift onto non-target plants is essential, especially when treating areas near desirable native vegetation.
Preventing Regrowth and Long-Term Control
After the initial removal, whether physical or chemical, the focus must shift to preventing the inevitable regrowth from any surviving rhizome fragments or seeds. Continuous monitoring of the area is necessary, with new shoots being addressed immediately before they can establish a robust new rhizome system. Any small sawgrass sprout should be spot-treated with an aquatic-approved herbicide or manually dug out, ensuring all roots are removed.
Altering the environment can discourage sawgrass return, particularly if the infestation is in a terrestrial area that is overly damp. Improving drainage in non-wetland areas makes the habitat less favorable for the moisture-loving sawgrass. For areas bordering large patches, installing a physical barrier, such as thick plastic or metal edging buried deep into the soil, can prevent new rhizomes from spreading. The barrier should extend at least a few inches above the soil line to prevent above-ground runners from crossing over.