[Wikipedia] South America native: Pontederia crassipes (formerly Eichhornia crassipes), commonly known as common water hyacinth is an aquatic plant native to South America, naturalized throughout the world, and often invasive outside its native range. It is the sole species of the subgenus Oshunae within the genus Pontederia.Anecdotally, it is known as the "terror of Bengal" due to its invasive growth tendencies. (link added by Mary Ann Machi)

[Cal-IPC] Invasiveness: Eichhornia crassipes (water hyacinth) is a floating freshwater perennial (family Pontederiaceae) that jams rivers and lakes with tons of floating plant matter. Floating mats of this plant can weigh up to 200 tons per acre. In California, Eichhornia crassipes typically is found below 660 feet (200 m) elevation in the Central Valley, San Francisco Bay Area, and south coast. Cal-IPC Rating: High (link added by Mary Ann Machi)