Restoration of an oak woodland invaded by Microstegium vimineum with and without herbicide control of the invader

Introduction Fire‐tolerant invaders of ecosystems that have undergone fire exclusion create a dilemma for land managers. One example is the invasion of rare oak ( Quercus L.) woodlands in the eastern United States by the invasive grass, Microstegium vimineum (Trin.) A. Camus, which increases in response to woodland restoration and can reduce native species diversity and wildlife habitat quality. Objectives Because M. vimineum is an annual that produces a persistent seed bank, whereas most oak woodland native plant species are perennials that do not require annual recruitment from seed, preemergent herbicides could control the invader and minimize collateral damage to native vegetation, but long‐term effects are unknown. Methods In 2018, I applied a preemergent herbicide (Barricade 4FL, Prodiamine 40.7%) one time to borders of patches of M. vimineum containing resident groundcover vegetation at two sites that differed in productivity and the stage of restoration. I measured responses of both M. vimineum and the residents in 2019, 2024, and 2025. Results The herbicide significantly reduced M. vimineum density in 2019. Despite a modest increase in 2025 at the more productive site, following a marked decline, M. vimineum had not fully recovered from the preemergent treatment at either site by 2025. The herbicide had immediate but short‐lived negative effects on some native species recruiting from seed at the less productive site. Conclusions A preemergent herbicide reduced the fire‐responsive invasive, M. vimineum , but also had a negative but short‐lived effect on seedling recruitment of some native species at one of the sites.