Best Management Practices for the Invasive Phalaris arundinacea L. (Reed Canary Grass) in Wetland Restorations

Abstract

Phalaris arundinacea (reed canary grass), a fast-growing, rhizomatous perennial grass, is a major concern for wetland restorations in the northern US because establishment by P. arundinacea often precludes colonization by sedge meadow vegetation in restored prairie pothole wetlands. This research developed a predictive understanding of P. arundinacea (a perennial grass) dominance in prairie pothole wetland restorations and investigated potential control techniques. A large-scale field experiment demonstrated that the most effective way to control P. arundinacea is a combination of later season herbicide applications to maximize rhizome mortality, and burning to reduce the P. arundinacea seed bank density. In a mesocosm experiment, P. arundinacea growth, but not recruitment from seed, was suppressed by the presence of native species established from seed, suggesting that P. arundinacea control will likely be necessary during native species establishment. In a uniform planting study, P. arundinacea exhibited rapid rates of growth which may contribute to its aggressive nature. Controlling P. arundinacea in the most efficient way is crucial to the establishment of native vegetation in wetland restorations. Reduction of P. arundinacea is a long-term process and one that is complicated by potential reinvasion of cleared sites, so control efforts must be as effective as possible. Moreover, P. arundinacea is still widely cultivated as a forage crop and planted as a conservation species, and these populations may serve as sources of continuing propagule pressure, further complicating localized eradication efforts.