How to Grow and Care for Waterweeds

Canadian waterweed (Elodea canadensis) has been introduced into Europe, Asia, Australia, and Africa, where it is considered an alien invasive plant. It is widely propagated and sold in the aquarium industry for its oxygenating properties, but in the wild, it outcompetes native plants; clogs up rivers, streams, and drainage channels; and obstructs boats.

The western waterweed (Elodea nuttallii) is an aquatic perennial that can grow rapidly, especially female plants. Native to North America, it has become invasive in Europe, crowding out native plants and competing for nutrients in the water. It blooms from spring to fall with purple flowers. It grows completely submerged underwater and is often used in aquariums.