Phalaris arundinacea (reed canarygrass) invasion is a primary barrier to wetland restoration in the midwestern United States

Increasing dominance by non-native plant species has plagued wetland restoration in the agricultural Midwest, USA. One such species, Phalaris arundinacea (reed canarygrass) forms persistent, low-diversity stands in restored wetlands, preventing achievement of restoration goals. We investigated the relationship between abiotic factors (hydrology, soil, canopy cover, and time since restoration) and Phalaris dominance in 22 restored wetlands in Illinois. Phalaris dominance increased with increasing latitude and soil fertility, and decreased with increasing canopy cover, suggesting that tree planting might control Phalaris. Indeed, data from experimental restoration plots indicated that increasing investment in tree planting inhibited Phalaris establishment, improving biodiversity outcomes.