There’s something almost beautiful about Parrot Feather at first glance — bright, lime-green fronds fanning out above the water’s surface like tiny ornamental ferns. But that visual charm is exactly what makes Myriophyllum aquaticum so deceptive. Beneath the surface, this South American native is rewriting the ecology of your pond, quietly strangling native plant communities, cutting off oxygen, and turning healthy aquatic environments into stagnant, choked mats of vegetation. Once it takes hold, it doesn’t ask permission to stay.

Legacy Waters Environmental Services works with property owners, HOAs, municipalities, and land managers across Maryland to identify and eliminate Parrot Feather infestations before they become defining features of the landscape. Understanding this plant — where it comes from, how it spreads, what damage it does, and what it takes to remove it — is the first step toward protecting the water bodies you depend on.

What Is Parrot Feather?

Parrot Feather (Myriophyllum aquaticum) is a perennial aquatic plant native to the Amazon River basin of South America. It belongs to the water-milfoil family Haloragaceae, making it a distant relative of Eurasian watermilfoil — another aggressive invader that plagues Maryland waterways. It was introduced to the United States around 1890 as an ornamental plant for aquariums and water gardens, and it has since spread to at least 26 states.

The plant’s common name comes from the distinctive appearance of its emergent stems, which fan outward in whorls of feathery, blue-green to bright green leaves, resembling small conifer branches or — with a little imagination — the plumage of a tropical bird. Each whorl typically contains four to six symmetrical leaves made up of 10 to 18 pairs of tiny leaflets. The emergent portions are sturdy and waxy, which is an important detail when it comes to management, as that waxy coating makes chemical control more technically demanding.

Emergent vs. Submerged Growth

One of the features that sets Parrot Feather apart from many aquatic plants is its ability to thrive in two distinct forms simultaneously. The emergent growth — the bright, feathery fronds that extend up to 30 centimeters above the water’s surface — is what most people notice first. Below the waterline, however, this plant produces long, branching submerged stems that can reach depths of around 1.3 meters and extend up to 16 feet in length.

The submerged leaves differ in appearance from the emergent ones, often taking on a reddish-brown tone as they trail through the water column. Both growth forms root into muddy substrates along pond edges, canal banks, and the shallow margins of lakes and streams. This dual architecture is not just cosmetic — it allows the plant to anchor itself firmly while simultaneously colonizing the water’s surface, creating a layered canopy that shades out nearly everything beneath it.

Where Parrot Feather Thrives

Myriophyllum aquaticum has a strong preference for calm, nutrient-rich water. It grows most readily in ponds, shallow wetlands, roadside ditches, irrigation canals, slow-moving streams, and backwater areas where currents are minimal and sunlight is abundant. Maryland’s mix of tidal tributaries, stormwater management ponds, farm ponds, and ornamental water features provides exactly the kind of habitat this plant exploits.

The plant is notably adaptable. It tolerates a broad range of water conditions, including varying pH levels, temperatures, and nutrient loads, and it can even establish itself in moist soil along the water’s edge when water levels drop. That flexibility means it isn’t confined to a single type of water body — it can move from a decorative garden pond to a drainage ditch to a larger lake system, establishing wherever conditions allow. While it performs best in shallower, warmer water with higher nutrient concentrations, it has demonstrated the capacity to persist in surprisingly adverse conditions.

How It Spreads

Parrot Feather does not rely on seeds to reproduce — in North America, the plant is predominantly female and rarely produces viable seed. Instead, it spreads almost entirely through vegetative fragmentation. A single small stem fragment, whether broken off by a paddleboat propeller, a bird’s foot, or the passage of a kayak, is fully capable of floating to a new location, taking root in soft sediment, and establishing an entirely new colony.

Human activity accelerates this process significantly. Boats, fishing gear, waders, and water garden equipment carry fragments between water bodies. Irresponsible disposal of aquarium plants is one of the most common pathways of introduction into new waterways. Once established, natural water currents carry fragments downstream, expanding the plant’s range with each passing season. This is why early detection matters so much — a small patch discovered in spring can become a substantial infestation by late summer.

The Real Cost of a Parrot Feather Infestation

Parrot Feather is not merely an aesthetic problem, though it certainly changes the character of a water body dramatically. The ecological and practical consequences of a mature infestation touch nearly every dimension of aquatic health.

Oxygen Depletion and Water Quality Decline

Dense mats of Parrot Feather intercept sunlight before it can penetrate the water column, suppressing the photosynthesis of submerged native aquatic plants. As those native plants die off, the decomposition process consumes dissolved oxygen in the water. The result is a gradual deterioration of water quality — lower oxygen levels, increased turbidity, and conditions that become increasingly hostile to fish and other aquatic organisms.

The thick surface mats also restrict natural gas exchange between the water and the atmosphere, compounding oxygen loss. In heavily infested ponds, this oxygen depletion can reach levels that stress or kill fish populations during warmer months, particularly at night when plant respiration consumes what little dissolved oxygen remains.

Disruption of Native Plant Communities

Native aquatic vegetation plays a structural role in healthy pond and wetland ecosystems. It provides habitat for invertebrates, shelter for juvenile fish, and food sources for waterfowl and other wildlife. Parrot Feather actively displaces these native plant communities by outcompeting them for light, space, and nutrients.

Once native vegetation is eliminated, the ecological relationships that depend on it begin to unravel. Invertebrate populations shift in composition and abundance, fish lose critical habitat, and water birds that rely on specific plant species for nesting and foraging find their habitat degraded. The result is not just a different-looking pond — it’s a fundamentally less functional one.

Flooding Risks and Infrastructure Impacts

Beyond the ecological damage, Parrot Feather poses a direct threat to drainage infrastructure. Dense mats in ditches, culverts, and canals impede water flow, causing water to back up and increasing flood duration and intensity during rain events. For municipalities managing stormwater systems, and for property owners with drainage easements running through or adjacent to their land, this is a practical maintenance problem with real financial implications.

Recreational use is similarly compromised. Swimming areas become unsafe and uninviting when clogged with dense vegetation. Fishing is disrupted as the plant entangles lines and alters fish behavior. Boating becomes difficult or impossible in heavily infested areas, and property values along affected waterways can decline as a result.

Identifying Parrot Feather in the Field

Knowing what Parrot Feather looks like is the first line of defense. The emergent portions are the most distinctive feature — bright green, feathery whorls of leaves arranged symmetrically around stiff, upright stems that extend above the water surface. The individual leaflets are fine-textured and pinnately arranged, giving each whorl the appearance of a tiny, layered fern or a miniature Christmas tree.

Telling It Apart from Similar Species

Parrot Feather can be confused with native and non-native aquatic plants, including Eurasian watermilfoil, Carolina fanwort, native water-milfoils, hornworts, and common bladderwort. The key distinguishing features are the robust, waxy texture of the emergent leaves and the height of the emergent growth above the water’s surface — characteristics that most native milfoils do not share.

If you notice plants along your pond margins with stiff, bright green, feather-like fronds reaching several inches above the water, don’t assume it’s harmless aquatic vegetation. When in doubt, reach out to a professional for confirmation before the colony expands. Misidentification can cost months of control progress.

Parrot Feather Management and Removal

Managing Parrot Feather effectively requires a clear understanding of its biology. Because the plant reproduces through fragmentation, certain removal methods can inadvertently worsen an infestation if not carefully executed. Physical cutting or harvesting without thorough collection of all fragments, for example, can scatter viable plant material across a water body and accelerate spread rather than reduce it.

Mechanical Removal

In some situations, mechanical removal — using seining nets, raking, or specialized aquatic harvesting equipment — can reduce Parrot Feather biomass. This approach works best when infestations are contained and all harvested material can be thoroughly removed from the water and disposed of properly on land, well away from any drainage pathway. Even then, root systems anchored in the sediment often remain viable and capable of regenerating new growth.

Mechanical methods are generally most appropriate as part of an integrated management strategy rather than as a standalone solution. For fully infested areas where fragmentation risk is already high, a professionally coordinated mechanical harvest can clear the surface and make follow-up treatments more effective.

Herbicide Treatments

Aquatic herbicides remain the most consistently effective tool for managing established Parrot Feather infestations. Formulations including 2,4-D and imazapyr have demonstrated excellent systemic results, while diquat and glyphosate offer broad-spectrum contact control. The key challenge in herbicide application is the plant’s waxy emergent leaf surface, which repels water-based products without the addition of a non-ionic aquatic surfactant to improve adhesion and uptake.

Timing is critical. Treatments applied in spring or early summer, when plants are actively growing and stems have not yet reached full maturity, produce the best results. For dense infestations, treating the water body in sections rather than all at once reduces the risk of oxygen depletion caused by rapid vegetation die-off, which can harm fish populations. Because this plant’s root system is persistent, a single treatment rarely achieves permanent control — follow-up monitoring and repeated applications over multiple seasons are typically necessary.

Drawdown and Other Approaches

Water level drawdown — lowering the water level to expose vegetation to drying and freezing — can be effective against Parrot Feather when executed over a sufficient period to fully desiccate the root system. This method is most practical in managed ponds where water levels can be controlled. In natural or semi-natural water bodies with less predictable hydrology, drawdown is less consistently useful as a primary control strategy.

Barrier cloth installed along pond margins, covered with pea gravel, can provide localized protection in targeted areas such as swimming zones or dock approaches, though this does not address existing infestations across a larger water body. Grass carp have been studied as a potential biological control and may offer some reduction in plant biomass at appropriate stocking densities, though their effectiveness against this plant specifically is variable and they require permits in Maryland.

Why Professional Removal Makes a Difference

The challenge with Parrot Feather — and with most aquatic invasives — is that well-intentioned but poorly planned removal efforts can make things significantly worse. Fragmenting a colony without removing all material, applying herbicides without appropriate surfactants or at the wrong growth stage, or disturbing the sediment in ways that redistribute propagules are all common mistakes that set infestations back on a trajectory of rapid regrowth.

Legacy Waters Environmental Services brings professional expertise to every removal project. Our team assesses each infestation individually, selecting methods appropriate to the site, the severity of the infestation, and the surrounding ecology. We handle the permitting process required by the Maryland Department of the Environment, coordinate safe and legal herbicide applications, and provide follow-up monitoring to ensure results are maintained over time. Whether you’re managing a private pond, a stormwater basin, a community lake, or a drainage corridor, the goal is the same: open water, healthier habitat, and a restored aquatic environment that functions the way it should.

If Parrot Feather — or any invasive aquatic plant — is encroaching on your property, early action is always more cost-effective than waiting. Contact Legacy Waters Environmental Services through or visit our Invasive Plant Removal page to schedule a free on-site consultation.

FAQs about Parrot Feather: What to Know

What does this plant look like in a pond?

Parrot Feather (Myriophyllum aquaticum) is recognizable by its bright green, feathery stems that extend several inches above the water’s surface in stiff, symmetrical whorls. Each cluster of leaves resembles a tiny conifer branch or layered fern. Below the waterline, the plant produces long, branching stems with softer, often reddish-brown leaves that can extend to depths of over four feet. The emergent growth has a noticeably waxy texture that distinguishes it from most native aquatic plants. Dense patches typically form floating mats along pond edges, drainage ditches, and slow-moving waterways.

How did Parrot Feather get into Maryland waterways?

Parrot Feather was originally introduced to the United States around 1890 as an aquarium and ornamental pond plant, and its spread into natural waterways has been driven primarily by human activity. Fragments attached to boats, trailers, fishing gear, and waders are transported between water bodies, where they detach and establish new colonies. Irresponsible disposal of aquarium plants into drains, streams, or natural ponds is another significant pathway. Once present in a watershed, the plant also spreads naturally as water currents carry stem fragments downstream to new locations.

Is this plant harmful to fish and wildlife?

Yes, significant infestations can cause serious harm to aquatic ecosystems. Dense surface mats block sunlight from reaching submerged native plants, which die off and decompose, consuming dissolved oxygen in the process. Low oxygen levels stress or kill fish, particularly during warm months. The displacement of native aquatic vegetation also degrades the habitat that invertebrates, juvenile fish, and waterfowl depend on for shelter and food. Over time, a heavily infested water body can shift from a biologically diverse aquatic community to one dominated almost entirely by Parrot Feather, with sharply reduced ecological function.

Can I remove Parrot Feather myself?

Small, isolated patches may be manageable with careful manual removal, but Parrot Feather’s primary mode of reproduction is vegetative fragmentation — meaning any stem pieces left in the water can root and form new colonies. Cutting or raking without thorough removal of all plant material often accelerates the spread rather than controlling it. Herbicide applications require the use of aquatic-approved formulations with non-ionic surfactants, and in Maryland, treatments in natural water bodies typically require permits from the Maryland Department of the Environment. For any infestation beyond a very small, entirely contained area, professional management is strongly recommended to avoid compounding the problem.

How long does it take to control a Parrot Feather infestation?

There is no single-treatment solution for established Parrot Feather infestations. Because the plant’s root system persists in the sediment even after above-ground growth is removed or killed, regrowth is common after initial treatments. Effective management typically involves a combination of methods — mechanical removal, targeted herbicide applications with appropriate surfactants, and ongoing monitoring — carried out over multiple growing seasons. The timeline depends on the size and density of the infestation, site conditions, and how consistently follow-up treatments are performed. Properties that commit to a structured, multi-year management plan consistently achieve the best long-term outcomes.