Several species of aquatic plants have an aggressive tendency and are considered invasive. If not regularly controlled, the invasive aquatic plants will take over a pond, smothering desirable plants and wildlife. That is why it is important to ensure floating plants you use in your pond or other water garden are not invasive and are safe to grow in your location.
Flowering pond plants that float along the surface of the water attract beneficial insects, such as bees and butterflies, to the area. Several of those plant species are not invasive, including pondlily and water poppy. Yellow pondlily (Nuphar lutea) grows in U.S. Department of Agriculture (USDA) plant hardiness zones 4 through 10 and produces heart-shaped leaves, which float on the water surface, and bright yellow flowers. Water poppy (Hydrocleys nymphoides) grows as a perennial in USDA zones 9 through 11 but can be used as an annual in other zones. This floating plant has thick, rounded foliage and yellow flowers that bloom for only one day.
Flowering Varieties for Full Sun
Floating aquatic plants that need full sun require at least 6 to 8 hours of sunlight each day to grow properly. Fanwort and Canadian pondweed are two sun-loving, floating aquatic plants that are not invasive. Fanwort (Cabomba caroliniana) grows best in USDA zones 6 through 10 either as an anchored aquatic plant or floating freely on the water surface. From May through September, fanwort produces white flowers that grow slightly above the water and its feathery foliage. Fanwort absorbs nutrients from the water and helps to control contaminants and algae. Canadian pondweed (Elodea canadensis) grows in USDA zones 4 through 10. It has lanced-shaped, deep-green foliage that floats on the water surface, and its green-to-white flowers appear in late spring or early summer. Like fanwort, Canadian pondweed helps keep water clear and free of algae by absorbing nutrients.
Flowering Varieties for Shade
Water lilies and cape pondweed are non-invasive aquatic plants that float on the water surface and tolerate shaded areas. Depending on the species, water lilies (Nymphaea spp.) grow best in USDA zones 3 through 10. Their padlike foliage floats on the water surface, and their blooms protrude out of the water. Most species of water lilies thrive in full sun, but a few cultivars, such as “Dauben,” tolerate shaded areas. Cape pondweed (Aponogeton distachyos) is suited for zones 6 through 10. Its green foliage floats on top of the water, and its sweetly fragrant blooms protrude slight above the water surface. Cape pondweed grows from tubers located at the bottom of ponds, lakes, swamps and other bodies of water.
Non-flowering floating plants are grown for their showy foliage, which floats on the water surface. Water fern and water clover are non-flowering aquatic plants and are not considered invasive. Growing best in USDA zones 7 through 10, water fern (Azolla filiculoides) has a matlike form, covering the water surface with foliage that changes color with the light conditions. In shaded areas, water fern is bright green, and the plant develops a rosy purple tint in full sun. Water fern is also known as mosquito fern; it helps to prevent mosquito eggs from hatching. Water clover (Marsilea quadrifolia) grows well in USDA zones 6 through 10, producing stalks that grow from the bottom of the pond to the water surface. The stalks have a single, cloverlike leaf at the top that floats on the water surface.
- California Invasive Plant Council: Don't Plant a Pest
- U.S. Fish and Wildlife Service: Aquatic Gardens, Not Aquatic Pests
- Clemson Cooperative Extension: Aquatic and Shoreline Plant Selection
- Missouri Botanical Garden: Aponogeton Distachyos
- University of Alaska-Fairbanks Integrated Pest Management Extension: Garden Wise -- Non-Invasive Plants for Your Garden
- U.S. Department of Agriculture Natural Resources Conservation Service: Plant Guide -- Yellow Pond Lily
- Missouri Botanical Garden: Hydrocleys Nymphoides
- Missouri Botanical Garden: Cabomba Caroliniana
- Missouri Botanical Garden: Elodea Canadensis
- U.S. Department of Agriculture Natural Resources Conservation Service: Plants Profile -- Elodea Canadensis Michx. Canadian Waterweed
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