Phalaris arundinacea
Despite the plant's tolerance of disturbance, populations occurring near roads and cultivated fields are vulnerable. Many populations in the Willamette Valley are threatened or already extirpated by agricultural and urban development. Over the last 150 years 99% of the wetland habitat in the Willamette Valley has been altered or destroyed. The possible future construction of a dam threatens a large population. Even in protected areas the plant is threatened by the invasion of non-native plant species. Such weeds include reed canary grass ("Phalaris arundinacea").