Species Profile: American Pondweed

Potamogeton nodosus

American Pondweed

Species Profile

Introduction

As a lake manager, I often encounter various forms of American Pondweed (Potamogeton nodosus). Now, let’s discuss the positives of this aquatic plant in your lake. It serves as a hiding spot for predatory fish, provides shade and habitat for forage fish, supports specific fishing techniques, and its growth is limited by depth. However, the success of American Pondweed depends on the lake environment. If your lake is shallow, it tends to overgrow, which can become a problem for anglers on the shoreline. It can become quite annoying when your lure gets all tangled up after you cast, making fishing less enjoyable.

Above American Pondweed (Potamogeton nodosus) in a viewing glass. Pictured, you can see the slender stems, fruit seed, and the elliptical to oval-shaped leaves (Provided by the author).

Above is American Pondweed (Potamogeton nodosus) growing in a dense mat (Provided by the author).

Where does it grow?

A native aquatic plant in North America that thrives as both a floating and submerged plant. Its foliage lies on the water’s surface, while its stems establish roots below it. This species can be found in many freshwater lakes, ponds, and streams. You will generally find American Pondweed growing in three to six feet of water. In some cases, if the water quality is excellent, American Pondweed can grow in up to twenty feet of water.

How tough is it?

This resilient aquatic plant thrives in Texas's warmer waters, displaying strong endurance. It outcompetes other submerged aquatic plant species by spreading and forming dense mats, effectively blocking sunlight from the other submerged plants. During late summer and early fall, the plant develops numerous unique vegetative structures known as “winter buds,” which are deeply buried in the sediment, specifically at the tips of their rhizomes. This enables the plant to enter a dormant phase during the winter and revive itself in the spring.

How is it beneficial?

Due to its ability to thrive in shallower waters, it effectively minimizes the growth of algae, thereby reducing the likelihood of harmful algae blooms in lakes and ponds. Additionally, its floating canopy provides shade, creating a suitable habitat and breeding area for a wide array of fish species. Furthermore, the dense mats formed by American Pondweed establish a microenvironment that attracts aquatic insects, frogs, and small fish, effectively serving as a natural deterrent for mosquitoes in the vicinity of your pond or lake. American Pondweed also attracts waterfowl like ducks and geese. 

How does it spread?

American Pondweed, just like other underwater plants, reproduces by breaking off pieces of its stem. This plant can create new plants, not just from seeds but also from fragments of mature plants and shoots. When fully developed, the seeds break off and float in the water. Animals like ducks and geese can consume these seeds or they attach to various animals' fur, feathers, and feet. Humans can unknowingly spread this aquatic plant through swimming, boating, and fishing. If plant fragments get accidentally broken off during these activities, they can grow wherever they end up.

How to identify it from other plants?

American Pondweed displays elliptical to oval-shaped leaves on the surface of the water. These leaves have a glossy appearance and a leathery texture. They measure approximately 4-7 inches in length, 1-2 inches in width and are arranged alternately along the slender stems. As the plant matures, spikes known as seed heads emerge from the water. These spikes range from brownish to greenish and are approximately 2-3 inches long.

What else should you know about this plant?

To ensure accuracy, it is essential to correctly identify the various species of pondweeds present in the water. The best way to control this aquatic plant is by using herbicides specifically made for it when it is at its strongest growth stage, usually in warmer water. Additionally, physically uprooting American Pondweed can be effective, although removing all remnants from the water is essential to prevent regrowth from residual roots and seeds.

About the author:

Kanyan attended Tarleton State University and received her Bachelor's in Fisheries and Wildlife Sustainability and Ecosystem Sciences. After graduation, she worked for Texas Parks and Wildlife as a Fish and Wildlife Technician at the Texas Freshwater Fisheries Center in Athens, TX. She decided to continue her education and pursue an MBA at TSU. She is now an assistant fisheries biologist for a private lake management company, Texas Pro Lake Management.

Kanyan is a member of the Texas Chapter of the American Fisheries Society, Texas Wildlife Association, Bass Brigade secretary-treasurer, serves as the social media coordinator for the American Fisheries Society Habitat Section, and the secretary of the Texas Aquatic Plant Management Society.