Submergent and Emergent Floating Pond Plants

Adaptation

• Lakes and rivers collect and provide a route for water to travel to the ocean. However, there are intermediate areas in every watershed, where the water table -- the level of groundwater -- sits close to the surface of the land. These wet lands do not absorb precipitation. It sits on top, and the level of the water falls only when water drains into streams and rivers. Plants along the edges of waterways and wetlands help maintain landforms, habitats and the communities that live in them. To do this, wetland plants must adapt to waterlogged soil or open water for at least part of the year.

Submergent Plants

• Submergent plants are also called aquatic plants. They breathe and gather food from the water and sink their roots into the waterlogged soil that underlies waterways, lakes and open wetlands. Many, such as bladderwort, hornwort and algae, are primitive plants that never evolved to live on land. Others, such as fanwort, or cobomba, appear indoors in aquariums. Pondweeds, naiads and eelgrass are North American natives that provide food for amphibians, fish, reptiles and waterfowl. As they die, they provide food for microscopic aquatic invertebrates, such as plankton, that fish and other larger life forms feed on. Non-native submergents, such as Eurasian Watermilfoil egera and curly-leaved pondweed, are invasive plants. Although non-native plants may be available to aquarium enthusiasts, they should never be allowed to escape into the wild, where they will crowd out native vegetation.

Emergent Plants

• Emergent plants include floating plants that are rooted in the shallows, such as the American lotus, duckweed and watercress. Emergents also grow in the shallows along the shorelines of waterways and wetlands. Blue flag iris, yellow water primrose and purple pickerel weed flower along shores; and sedges, rushes and cattail stand erect. Emergent plants must be adaptable, because water levels rise and fall as seasons change. Submerged portions of these plants provide habitats for invertebrates that begin the food chain for other wetland species. Fruits and roots provide food for aquatic and land-dwelling animals.

Considerations

• The use of submergent and emergent plants when landscaping water features lends authenticity to the project. More important, these plants survive and self-propagate more successfully than nonwetland plants, and they help establish a mini-ecosystem that will make maintenance easier. Whether restoring a shoreline or planting a koi pond, using native submergent and emergent plants provides a habitat for fish, waterfowl and the invertebrates upon which they feed.