Is your St. Augustine lawn more of a St. Augustine takeover? This grass, while beautiful and well-suited to warm climates, can quickly become a problem when it spreads where it's not wanted. Whether it's encroaching on your flower beds, sneaking into your vegetable garden, or simply taking over areas where you'd prefer a different ground cover, controlling St. Augustine grass is essential to maintaining the landscape you desire.
A rogue St. Augustine lawn not only looks untidy, but its aggressive growth habit can also choke out other plants, stealing their nutrients and sunlight. Ignoring the problem only allows it to worsen, leading to more extensive removal efforts down the road. Fortunately, there are a variety of effective methods to eliminate unwanted St. Augustine, ranging from manual removal to targeted herbicide applications, depending on the scale and location of the problem.
What are the best strategies for eliminating St. Augustine grass?
What's the best herbicide to kill St. Augustine grass completely?
The most effective herbicide for completely killing St. Augustine grass is glyphosate, a non-selective systemic herbicide. Products containing glyphosate, such as Roundup, will kill virtually any plant they contact, including St. Augustine. Because it is non-selective, careful application is crucial to avoid damaging desirable plants.
Glyphosate works by being absorbed through the foliage of the plant and then translocating down to the roots, effectively killing the entire plant system. Multiple applications may be necessary, especially for well-established St. Augustine grass. It's important to follow the instructions on the product label carefully regarding dilution rates, application methods, and safety precautions. Typically, you should apply glyphosate on a calm day to prevent drift onto other plants. The grass should be actively growing for the herbicide to be most effective; avoid application during periods of drought or dormancy.
Before using glyphosate, consider protecting any nearby plants you want to keep. This can be done by physically covering them with a tarp or cardboard during application. After applying the herbicide, it can take several days or even weeks for the St. Augustine grass to completely die off. Once the grass is dead, you can remove the dead material and prepare the area for replanting or other landscaping purposes. Remember to always wear appropriate personal protective equipment (PPE) such as gloves and eye protection when handling herbicides.
How can I remove St. Augustine grass without using chemicals?
Removing St. Augustine grass without chemicals requires a persistent and physical approach. The most effective methods involve smothering the grass to deprive it of sunlight, manual removal by digging, or solarization using the sun's heat. Choose the method best suited to the size of the area and your physical capabilities.
Smothering St. Augustine grass is a practical option for larger areas where digging would be too labor-intensive. This involves covering the grass with an opaque material like cardboard, heavy-duty tarps, or black plastic sheeting. Secure the edges of the material to prevent light from penetrating and to keep it in place during windy conditions. Leave the covering in place for several weeks, or even months, depending on the time of year and sunlight intensity. The lack of sunlight will eventually kill the grass. Afterwards, the dead grass can be removed and the area prepared for planting. For smaller patches or areas where you need immediate results, manual removal is the most effective. Use a shovel or garden fork to dig up the St. Augustine grass, being sure to remove the roots and rhizomes. St. Augustine spreads via rhizomes (underground stems), so any remaining pieces can regrow. Thoroughly remove all visible parts of the grass and its root system. Consider using a sturdy utility knife to cut the grass into manageable sections before digging, making the removal process easier. After removal, fill the area with topsoil and compact it to prevent future settling. Solarization is another method, particularly effective during the hottest months of the year. Thoroughly water the area you want to clear, then cover it with clear plastic sheeting. This traps solar heat, effectively "baking" the grass and soil. The heat will kill the St. Augustine grass and any weed seeds in the soil. Leave the plastic in place for 6-8 weeks during peak sunlight hours for optimal results. Once the process is complete, remove the plastic and till the soil before replanting.What's the most effective way to prevent St. Augustine grass from spreading into my flower beds?
The most effective way to prevent St. Augustine grass from invading your flower beds is to install a physical barrier, such as edging, combined with vigilant maintenance to remove any runners that attempt to cross the barrier.
Creating a physical barrier is crucial because St. Augustine grass spreads aggressively through above-ground runners called stolons. Edging materials like plastic, metal, stone, or even deeply buried wood can physically block these runners. For best results, bury the edging at least 6 inches deep, leaving a couple of inches exposed above ground. This depth deters the stolons from simply growing under the barrier. Regularly inspect the border and prune or remove any runners that manage to creep over or under the barrier. In addition to the physical barrier, regular maintenance is key. Keep an eye out for any St. Augustine grass that has already infiltrated your flower beds. Hand-pulling is often effective for small infestations, ensuring you remove the entire runner and its root node. For larger patches, you may need to dig up the affected area, being careful to remove all traces of the grass. Applying a pre-emergent herbicide in early spring can help prevent new seedlings from sprouting in the flowerbeds, adding another layer of protection.Will solarization effectively kill St. Augustine grass in my lawn?
Yes, solarization can be an effective method for killing St. Augustine grass, but its success depends on proper execution and ideal weather conditions. The process involves trapping solar heat under clear plastic to raise soil temperatures to lethal levels for the grass and many weed seeds.
Solarization works by creating a mini-oven effect on your lawn. The clear plastic traps sunlight, causing the soil temperature to rise significantly – often exceeding 140°F (60°C) at the surface. These high temperatures, sustained over several weeks, damage the St. Augustine grass's cellular structure, ultimately leading to its demise. The extended heating also helps to deplete the weed seed bank in the soil, offering a more comprehensive lawn renovation strategy. However, remember that solarization is most effective during the hottest months of the year (typically summer). Success also depends on ensuring complete coverage with the plastic, sealing the edges to prevent heat escape, and allowing sufficient time (usually 4-8 weeks) for the process to work. Factors such as soil moisture content, initial grass health, and local climate conditions can also influence the outcome. While effective, solarization isn't a quick fix, but a longer-term approach to creating a weed-free seedbed.How long does it take to completely kill St. Augustine grass in a large area?
The time required to completely kill St. Augustine grass in a large area varies depending on the method used, but generally takes between two weeks to several months. Factors influencing the timeline include the chosen herbicide, environmental conditions, the density and health of the grass, and the thoroughness of application.
Killing St. Augustine grass typically involves the application of a non-selective herbicide like glyphosate (Roundup). After the initial application, you'll usually see signs of decline within a week or two, with yellowing and browning of the grass blades. However, complete kill, especially in a dense area, requires more than one application. Glyphosate works by systemic action, meaning it needs to be absorbed by the leaves and transported throughout the plant to kill the roots. Respraying after a couple of weeks ensures that any surviving grass or newly emerged shoots are also targeted. Environmental conditions significantly impact herbicide effectiveness. Warm, sunny weather promotes faster absorption and translocation of the herbicide. Avoid applying herbicides immediately before or after rain, as this can wash away the product. For large areas, consider breaking the process into sections to manage the workload and ensure even coverage. Multiple applications, spaced according to the herbicide's instructions, are crucial for a complete kill and to prevent regrowth. In some cases, especially with established lawns, solarization might be needed after herbicide use to fully eradicate the grass and its root system.What steps should I take after killing St. Augustine to prepare the area for new grass?
After successfully killing St. Augustine grass, the key steps are to remove the dead material, prepare the soil, and then amend it for optimal new grass growth. This includes removing the thatch layer, testing the soil's pH and nutrient levels, and adding amendments like compost or fertilizer based on the soil test results.
Successfully preparing the area post-St. Augustine eradication is crucial for the successful establishment of your new lawn. Removing the dead St. Augustine is more than just aesthetics; it removes a thick layer of thatch that can inhibit new seed germination or prevent young roots from reaching the soil. You can remove the dead grass by raking vigorously, using a dethatching rake, or even renting a power rake for larger areas. Aim to remove as much of the dead material as possible, leaving bare soil exposed. Soil preparation is equally important. Tilling or aerating the soil will help improve drainage and aeration, creating a better environment for new roots to penetrate. However, before tilling, conduct a soil test. This test will reveal the soil's pH, nutrient levels (nitrogen, phosphorus, potassium), and organic matter content. Most local extension offices or garden centers offer soil testing services. Based on the test results, you can amend the soil accordingly. For example, if the soil is acidic, you may need to add lime to raise the pH. If it's deficient in nutrients, incorporate a balanced fertilizer or compost. Adding a layer of compost will also improve soil structure and water retention. Aim for a smooth, even surface for planting. Finally, consider weed control. Even after killing the St. Augustine, weed seeds may still be present in the soil. You can apply a pre-emergent herbicide specifically designed for use before planting grass seed, but be sure to choose one that won't harm your desired grass type. Carefully follow the instructions on the herbicide label. Proper preparation will significantly increase the chances of a lush, healthy new lawn.Is there a selective herbicide that will kill St. Augustine without harming other grasses?
No, there is no readily available selective herbicide that will kill St. Augustine grass without harming *all* other common lawn grasses. The herbicides that are effective against St. Augustine are generally non-selective, meaning they will kill or severely damage any grass or plant they come into contact with. Targeting St. Augustine specifically often requires careful application techniques and sometimes accepting some damage to desirable grasses.
When dealing with unwanted St. Augustine in areas where you want to preserve other grasses, your options are limited. Glyphosate (Roundup) is a common non-selective herbicide that can be used, but extreme caution must be exercised. This means carefully spot-treating only the St. Augustine, using a paint brush or shield to prevent overspray onto desirable grasses. Multiple applications may be necessary, and some damage to surrounding grasses is almost unavoidable. Consider the size of the St. Augustine patch. If it’s small, manual removal by digging it out might be the best option, followed by reseeding or patching with the desired grass type. Another strategy involves managing the environment to favor the desired grasses and weaken the St. Augustine. St. Augustine thrives in moist, shady conditions. Improving drainage, increasing sunlight penetration through pruning, and adjusting your watering schedule can help create an environment where other grass types can outcompete the St. Augustine. Furthermore, different grass types have different fertilizer needs. Soil testing to determine nutrient deficiencies and applying fertilizer appropriate for your desired grass can put St. Augustine at a disadvantage.And that's it! Getting rid of St. Augustine grass can be a bit of a process, but with a little patience and the right approach, you can reclaim your lawn. Thanks for reading, and good luck! We hope you'll come back soon for more tips and tricks to keep your yard looking its best.