Curly-Leaf Pondweed is an invasive aquatic perennial plant that can grow offshore in depths of up to 15 ft (4.5 m). It has the unique ability to form new plants under the ice in the winter, making it one of the first nuisance plants to emerge in the spring. Curly-Leaf Pondweed was introduced to the United States by hobbyists who used it as an aquarium plant, and it has since been reported in almost all of the continental United States.