How can I control nutgrass in Texas?
Answer: Nutgrass is the common term for what is technically nutsedge. There are two types on nutsedge in Texas: yellow nutsedge and purple nutsedge. New plants from both types arise from underground tubers. The tuber’s skin contains a chemical substance that inhibits sprouting. Soil moisture “washes” this inhibitor off the tuber allowing it to sprout. This is one reason why the plant thrives in a wet area of the lawn or garden and proliferates during wet spring seasons.
When a nutsedge shoot reaches the surface, it forms a basal bulb, from which grow roots and thin, wiry underground stems with new tubers at their ends. In one year, the outward growth from one tuber has the potential to produce 1,900 new plants and 7,000 new tubers. Now you can see why it’s so difficult to control! In order for control to be effective, mechanical control must outlast the tuber’s ability to regenerate, or an herbicide product must translocate down and kill the tuber.
Limiting tuber production and draining tube energy reserves by repeatedly removing small plants before the six-leaf stage (every two to three weeks in summer) can eventually control populations. Mature tubers can re-sprout up to 12 times. Shading or solarization can help reduce populations by weakening shoots and decreasing new tuber formation, but mature tubers will not be eliminated. Cultivation can worsen an infestation if not repeated enough to exhaust tuber reserves and prevent new tuber formation.
If you decide to use herbicides, always read the labels of the product and follow the instructions. Bonide Sedge Ender is an effective control of nutgrass and sedges. It kills nutgrass and prevents it from coming back. A new product from Monterey is Nutgrass Killer Selective Herbicide, which can be used in established lawns or around woody ornamentals. Sometimes these products do not work as effectively as hoped. Some herbicides need to be applied more than once or twice, depending on weather conditions and severity of the infestation.
ATTRA’s Biorationals: Ecological Pest Management Database is a searchable tool that will help you identify low-risk materials for pests and weeds that can be integrated with ecological pest-management-strategies.
To learn more about weed management, check out the ATTRA publication Sustainable Weed Management for Small and Medium-Scale Farms. It discusses several strategies, both proactive and reactive, as alternatives to conventional tillage systems. Options include mulching, competition, crop rotations, and low-toxicity control alternatives.
Note: the mention of specific brand names is for educational purposes only and does not constitute endorsement by NCAT, ATTRA, or USDA.