Yellow floating hearts (Nymphoides peltata). Photo: Glen Miller, Oregon Department of Agriculture.

Invasive aquatic plants are often fast growing, aggressive and can dramatically change water bodies after their introduction. Invasive aquatic plants can completely fill the water column or cover the surface so that fish are driven from the area. Often swimming, boating and other recreation uses can be negatively affected or even dangerous in areas with invasive aquatic plants.

These plants may be introduced intentionally or escape from cultivation. One in the wild, nonindigenous plants can colonize aquatic communities where they compete with and often displace native species. Hydrilla (Hydrilla verticillata), water-hyacinth (Eichhornia crassipes) and Eurasian watermilfoil (Myriophyllum spicatum) are examples well known for their ability to alter physical and biological functions of aquatic systems.