Common lespedeza (Kummerowia striata [Thunb.] Schindl.), a member of the legume family, is a warm-season annual weed common throughout Louisiana. Lespedeza prefers areas with dry, underfertilized, compacted soils and is often an indicator of low nitrogen levels in the soil. Its stems become woody as it matures, allowing it to better compete with and choke out turfgrass. Lespedeza also has a low growth habit, which makes it difficult to cut when mowing. It emerges from seeds in early spring and becomes established in lawns by summer.
Common lespedeza can be identified by its small, dark-green, oval-shaped leaves that are trifoliate (occurring in sets of three leaflets) with smooth edges. Leaflets have distinct parallel veins that can be nearly perpendicular to the leaflet midvein. As lespedeza matures, its stems become hardened and woody. It typically grows in low-growing, prostrate mats. Lespedeza produces small pink to purple flowers at leaf axils beginning in late summer.
For more information on Common lespedeza identification and characterization visit the USDA Plants Database at https://plants.usda.gov.
The best way to prevent or reduce weed encroachment is to maintain a healthy lawn through regular mowing and proper fertilization and soil pH management. Properly maintaining a lawn through these cultural practices promotes dense and vigorous turfgrass and allows the lawn to better compete with weeds. Below are the recommended mowing heights and nitrogen fertility rates recommended for each turfgrass species. In addition to these lawn care practices, manual removal of weeds may also be necessary.
In addition to cultural practices, herbicide applications may be required to achieve effective weed control. Apply post-emergence herbicides when common lespedeza is observed in the lawn. Post-emergence herbicides like metsulfuron or a product similar to Celsius, which contains thiencarbazone, dicamba and iodosulfuron, are more effective on young, actively growing weeds. Follow-up applications may be necessary to achieve control. Populations of lespedeza that are allowed to persist into late summer can be very difficult to manage. When using any herbicide, you must follow the manufacturer's labeled directions.
For more information regarding pesticides for turfgrass please reference the Louisiana Suggested Chemical Weed Control Guide.
For information regarding weed identification and control options please contact your local LSU AgCenter Extension Parish Office. To find your local LSU AgCenter Extension Parish Office visit here.