American Pondweed
Potamogeton nodosus
American pondweed can be found throughout the entire United States. It is sometimes considered a nuisance species and poses a threat to many native species of submerged aquatic vegetation. (Photo courtesy Ken-ichi Ueda/iNaturalist CC BY)
(Photo courtesy Jennifer Linde/iNaturalist CC BY-NC)
(Photo courtesy Cassi Saari/iNaturalist CC BY-NC)
(Photo courtesy Cassi Saari/iNaturalist CC BY-NC)
(Photo courtesy Cassi Saari/iNaturalist CC BY-NC)
Also known as longleaf pondweed, American pondweed is a rooted, perennial herb that has both submerged and floating leaves.
Appearance
The leaves of American pondweed are attached to a stem that can grow up to 6 feet long. Floating, oval-shaped leaves are 4 to 7 inches long and 1 to 2 inches wide, while the less abundant, submerged leaves are smaller and blade-like. Flowers emerge from the water in densely packed, club-like spikes. Seed heads are brownish red and extend above the water on slender stalks.
Predators
American pondweed is often a food source for fish, waterfowl and turtles. Because it is considered a nuisance species, it is eradicated by humans with herbicide. It is also susceptible to aphid infestation.
Reproduction and Life Cycle
Reproduction occurs through producing new shoots, fragmentation and seeds.
Did You Know?
- Although native to the Bay region, American pondweed is considered a threat to other native submerged aquatic vegetation because of its tendency to form dense mats that block the sunlight these plants need to grow. However, these dense mats are considered a good source of shelter and food for fish, diving ducks and invertebrates.
Sources and Additional Information
- Aquatic Pest Control by Patrick J. Marer and Kathy Keatley Garvey
- American Pondweed – San Jacinto River Authority
- American Pondweed – Texas A&M AgriLife Extension Service
Quick Facts
Species
Native
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Size
Stem up to 6 feet in length; leaves 4 to 7 inches in length
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Habitat
Lakes, ponds, ditches, streams and shallow water; can also grow in rapid and deep waters
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Range
Found throughout the United States
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Status
Stable