Eelgrass is one of the most important and most misunderstood aquatic plants in Lake Guntersville. In casual conversation, the name is often used as if it refers to a single, simple plant. In reality, the Guntersville eelgrass story is more complicated. Native American eelgrass has long been part of southeastern freshwater systems, but in recent years TVA and other researchers have drawn attention to an invasive hybrid eelgrass that has spread through portions of the Tennessee River system, including Lake Guntersville.
That distinction matters. Native eelgrass is a familiar part of freshwater habitat in the Southeast. The invasive hybrid, by contrast, has become a significant management issue, associated with dense growth, shoreline problems, recreational interference, and broader ecological change. On Lake Guntersville, eelgrass is not just a plant. It is one of the clearest examples of how aquatic vegetation can be both habitat and burden at the same time.
Quick facts
Common name: Eelgrass
Native species: Vallisneria americana
Invasive hybrid discussed in TVA and recent scientific coverage: Vallisneria × pseudorosulata
Plant type: Rooted, submerged aquatic plant
Key identification clue: Long, ribbon-like, tape-like leaves
Growth habit: Underwater beds and patches; in some cases dense surface-reaching growth
Why it matters on Lake Guntersville: Habitat value, invasive spread, shoreline and boating interference, and ongoing management attention
Identification
Native eelgrass has long, limp, ribbon-like leaves that rise from the base rather than branching along a stem. Outdoor Alabama describes the leaves as tape-like, nearly an inch wide, and up to several feet long. Some of the longer leaves may float at or just below the surface, and the flower or fruit appears at the end of a long, thread-like stalk that is often coiled.
This shape makes eelgrass easier to recognize than many other submerged plants. It does not have the finely feathered look of Eurasian milfoil, and it does not have the whorled, toothed leaves of hydrilla. In broad visual terms, eelgrass looks like underwater ribbons.
What is harder to determine by sight alone is whether eelgrass observed in Lake Guntersville is the native species or the invasive hybrid that has become an active concern in the Tennessee Valley. That distinction is treated in TVA and scientific literature as a specialized identification issue rather than something reliably determined at a glance from shore.
What it looks like in the water
In clear water, eelgrass often appears as smooth green straps rising from the bottom and moving with the current. In lighter growth, it can look graceful and open. In heavier growth, it forms broader beds and can become much more conspicuous near shorelines and in shallow water.
That visual simplicity is part of what makes eelgrass distinctive. Where milfoil looks soft and feathery and hydrilla looks leafier and more structured, eelgrass tends to appear clean-lined and blade-like.
Native eelgrass and invasive hybrid eelgrass
The eelgrass story on Lake Guntersville now includes two different realities.
The native species is American eelgrass, Vallisneria americana. It is part of the natural freshwater flora of the Southeast and is treated by Outdoor Alabama as a normal native aquatic plant. TVA’s plant identification materials also note that eelgrass provides food and shelter for fish and waterfowl.
The invasive form that has drawn recent management attention is shortstemmed eelgrass, Vallisneria × pseudorosulata, a hybrid between two nonnative eelgrass species. TVA’s recent reporting describes it as a rapidly growing hybrid that has spread through Guntersville, Nickajack, and Wheeler reservoirs. The 2025 scientific literature on the plant likewise identifies it as an invasive hybrid that has become a major issue in the southeastern United States.
This is one of the most important distinctions in the vegetation story of modern Lake Guntersville. Not all eelgrass on the lake should be assumed to represent the same ecological reality.
Ecology and growth habit
Eelgrass is a rooted submerged plant associated with shallow to moderately shallow water where enough light reaches the bottom for sustained growth. Native eelgrass is valued as habitat in southeastern freshwater systems, and TVA notes that it provides food and shelter for fish and waterfowl.
The invasive hybrid has drawn attention because of how effectively it spreads. TVA says it expands by sending out new shoots and by fragments that break away and start elsewhere. Recent scientific work on Vallisneria × pseudorosulata likewise describes rapid reproduction through offshoot formation and floating propagules capable of drifting before becoming established.
That kind of vegetative spread helps explain why eelgrass can move from scattered growth to a much larger management issue in a reservoir setting. In a system shaped by current, shoreline use, and boat traffic, fragments and propagules can help establish new colonies in other areas.
Eelgrass in Lake Guntersville
Lake Guntersville has become one of the central places in the recent story of invasive hybrid eelgrass in the Southeast. TVA has reported that the problem plant was first noticed in the Guntersville and Nickajack system roughly a decade before its 2025 update and has since spread throughout Guntersville, Nickajack, and Wheeler reservoirs.
USGS records also document Vallisneria × pseudorosulata from Guntersville Lake, including Alabama records from 2019 and 2023. Those records confirm that the hybrid’s presence in the reservoir is not just anecdotal or local shorthand; it is documented in formal occurrence records.
TVA’s 2023 coverage also reported that aquatic plant biologists at Guntersville had recently been unable to find or collect native Vallisneria americana, stating that the hybrid had displaced it. That finding is striking and important, though it is best understood as a reported condition at that time rather than a permanent statement about every part of the reservoir.
Why it matters
Eelgrass matters on Lake Guntersville because it occupies both sides of the aquatic vegetation story.
In its native form, eelgrass is part of a functioning freshwater plant community and contributes habitat value. In its invasive hybrid form, it has become a source of concern for managers, shoreline users, and boaters. TVA’s recent reporting says the hybrid has affected recreation, property owners, shorelines, and even hydroelectric operations.
This tension is part of what makes eelgrass such a defining Guntersville plant. It can be associated with habitat and structure, yet it can also become dense enough to interfere with access, boating, and shoreline use. On Lake Guntersville, those two realities now exist side by side within the same plant category.
Management
TVA says invasive aquatic plant overgrowth is managed with a combination of EPA-approved aquatic herbicides, harvesting, and continued surveying and monitoring. TVA’s treatment schedules are published during the growing season, and management is concentrated in public access and developed use areas where invasive plant growth interferes with reservoir use.
Recent TVA reporting on Guntersville eelgrass also describes collaboration with Mississippi State researchers testing herbicide combinations and notes that harvesting, herbicide treatment, natural factors, and partnerships have all contributed to recent reductions in collected eelgrass volume at Lake Guntersville.
Management, however, is not the same as eradication. TVA continues to treat invasive eelgrass as an active issue on the reservoir, and the larger goal remains control of nuisance growth rather than removal of all aquatic vegetation.
FAQ
Is eelgrass native to Lake Guntersville?
American eelgrass, Vallisneria americana, is native to the Southeast. But Lake Guntersville also has a documented invasive hybrid eelgrass, Vallisneria × pseudorosulata.
How can eelgrass be identified?
Its most recognizable feature is its long, ribbon-like, tape-like leaves.
How is eelgrass different from hydrilla?
Eelgrass has smooth ribbon-like leaves rising from the base. Hydrilla has narrower leaves arranged in whorls along a stem.
How is eelgrass different from Eurasian milfoil?
Eelgrass has long blade-like leaves. Eurasian milfoil has finely divided, feather-like leaves.
How does invasive eelgrass spread?
TVA and recent scientific work indicate that it spreads through new shoots, fragments, offshoots, and floating propagules.
Why is eelgrass a problem on Lake Guntersville?
The invasive hybrid can form heavy growth that interferes with recreation, shoreline use, boating, and infrastructure.
Does TVA manage eelgrass on Lake Guntersville?
Yes. TVA has reported active treatment, harvesting, monitoring, and research partnerships related to invasive eelgrass on Guntersville.
Closing
Eelgrass is one of the most revealing plants in the story of Lake Guntersville. It is at once a native habitat plant, an invasive management problem, and a reminder that not all “grass” on the lake means the same thing. Few aquatic plants better capture the complexity of Guntersville itself: a reservoir where ecology, recreation, and management are always closely intertwined.
Works Cited
- Tennessee Valley Authority, Aquatic Plant ID
- Tennessee Valley Authority, Tackling Invasive Eelgrass
- Tennessee Valley Authority, The Eelgrass Battle
- Outdoor Alabama, Eel Grass
- USGS NAS, shortstemmed eelgrass (Vallisneria × pseudorosulata) species profile
- USGS NAS, Alabama collection records for shortstemmed eelgrass
- Gebhart et al. (2025), Invasive eelgrass hybrid (Vallisneria × pseudorosulata) in the southeastern United States