Several producers in Oregon County and surrounding areas have reported growing concerns this year about sericea lespedeza in fescue pastures and hay fields.
As this invasive perennial continues to spread, proper herbicide timing and selection of the right active ingredient are essential for successful control.
Herbicide recommendations vary depending on the plant’s stage of growth. In early summer, sericea lespedeza is most effectively controlled with herbicides containing triclopyr. As the growing season progresses, however, the plant becomes more difficult to control with the same products.
Grazing or mowing before mid-July can reduce seed production and weaken plant vigor. Allowing about four weeks of regrowth after grazing or mowing improves herbicide uptake and increases the effectiveness of late-season applications.
During late summer, from August through September, herbicides containing metsulfuron-methyl generally provide more effective control because the plants have entered the flowering stage of their life cycle.
Herbicides are only one part of a long-term management strategy. While they can significantly reduce sericea lespedeza populations, they will not automatically restore desirable forage species.
Producers should also evaluate soil pH and fertility, maintain proper grazing or hay management practices and consider reseeding desirable forage species where stand density has been reduced. Combining these practices with timely herbicide applications offers the best opportunity for long-term suppression of sericea lespedeza and improved pasture productivity.
As always, read and follow the herbicide label for application timing, rates, grazing and haying restrictions, and any precautions related to forage species or nearby sensitive plants.
For more information, contact a local MU Extension agronomy field specialist.
