St. Augustinegrass (Stenotaphrum secundatum), which grows in U.S. Department of Agriculture plant hardiness zones 8 through 10, is highly adapted to warm and humid subtropical climates such as Florida and the coastal regions along the Gulf of Mexico. Although it is highly preferred in certain areas and offers many advantages, it is still susceptible to a few weeds, including bermudagrass. Triclopyr 4, a selective herbicide, will damage St. Augustinegrass and isn't appropriate for weed control in these lawns.
Triclopyr 4 Basics
Triclopyr 4 is labelled for use on woody plants, annuals and perennial broadleaf weeds in areas including ranges, pastures, forests, ornamental turf, rights-of-way and more. Triclopyr 4 contains triclopyr BEE, or triclopyr butoxyethyl ester. The product contains 4 pounds of triclopyr acid equivalent per gallon. Triclopyr 4 also contains oxyacetic acid and butoxyethyl ester; active ingredients make up just over 61 percent of the product.
Triclopyr 4 Uses
Triclopyr 4 is a powerful selective herbicide that is often used as broadleaf weed control in home lawns and other ornamental turfs. Among its many qualities as an herbicide is its ability to control unwanted bermudagrass (Cynodon spp.), which is a common, warm-season turf grass hardy in USDA zones 7 through 10. Despite it being commonplace as a turf grass species, bermudagrass can quickly become invasive, thus the need for control. For example, bermudagrass can quickly overtake a St. Augustinegrass lawn due to its spreading rhizomes and stolons.
Triclopyr 4 and St. Augustinegrass
Unfortunately, triclopyr is not labelled for use on St. Augustinegrass and can severely damage this desirable turf species. In addition, it can also damage zoysiagrass (Zoysia spp.), hardy in USDA zones 6 through 9, centipedegrass (Eremochloa ophiuroides), hardy in USDA zones 7 and 8, and others. Triclopyr mimics a plant growth hormone and results in the plant growing uncontrollably and in a disorganized fashion, which results in plant death.
For weed control in St. Augustinegrass, you fortunately have a few options that won't damage your turf as Triclopyr 4 would. Examples of pre-emergent herbicides for St. Augustinegrass include atrazine, benfin and pendimethalin. Atrazine is also an acceptable post-emergent herbicide for St. Augustinegrass. Before purchasing any product based on their active ingredients, however, read the label to ensure the product is labelled for use on St. Augustinegrass.
- University of Florida IFAS Extension: St. Augustinegrass for Florida Lawns
- YardCare.com: Warm-Season Grasses
- Alligare: Triclopyr 4 Specimen Label
- University of Tennessee Extension: Controlling Bermudagrass in Zoysiagrass and Tall Fescue Turf
- National Pesticide Information Center: Triclopyr Technical Fact Sheet