Smooth Brome (Bromus inermis) in Tallgrass Prairies: A Review of Control Methods and Future Research Directions

Smooth brome (Bromus inermis) is a cool-season rhizomatous grass of Eurasian origin that has escaped intentional plantings and spread widely in natural areas. A large body of work exists regarding smooth brome's biology and response to conservation management strategies designed to reduce its competitive effects on native prairie species, particularly for the tallgrass prairies of North America. Here we summarize that literature to improve restoration practice. In tallgrass prairie, smooth brome benefits from the early start of its growing season and its rhizomatous growth form, making it a strong competitor against native warm-season grasses. Late-spring burns timed to target smooth brome when root reserves are at their lowest have shown promise as a control strategy. Uncertainty remains, however, about the relative efficacy of fire, herbicide, mowing, or grazing to accomplish late-spring defoliation, the effect of repeated treatments, and the potential benefits of treatment combinations. The responses of resident or seeded natives to brome control treatments and/or the resulting decreases in brome cover also remain largely unexamined. Research focused on the questions we highlight would reduce costs associated with the control of smooth brome and increase confidence in the outcomes of restoration efforts.