There’s a reason lily pads show up in fairy tales and impressionist paintings. Floating serenely across the surface of a pond or lake, they carry an undeniable beauty — those broad, waxy leaves catching sunlight while frogs perch at their edges. But if you manage a pond, own lakefront property, or are responsible for a waterway’s health, that postcard image can quickly become a nightmare. Lily pads are one of nature’s most deceptive invasive aquatic plants, and by the time they’ve claimed half your water’s surface, the damage beneath the waterline is already well underway.

At Legacy Waters Environmental Services, we’ve seen what unchecked lily pad growth does to ponds and lakes across Maryland and the Mid-Atlantic region. We’ve worked with homeowners, HOAs, golf courses, and municipalities who all said the same thing when they called us: “They just showed up. Now they’re everywhere.” That story is more common than most people realize — and it’s exactly why we’re breaking it all down here.

What Are Lily Pads, Exactly?

Lily pads belong to the Nymphaeaceae family, a group of aquatic flowering plants found across temperate and tropical regions worldwide. The most commonly problematic species in the Mid-Atlantic are the fragrant water lily (Nymphaea odorata) and the yellow pond lily, also known as spatterdock (Nuphar lutea). Both species are rooted in pond or lake sediment and send up long, flexible stems that allow their signature round leaves — the “pads” — to float on the surface.

The flowers are genuinely stunning. White, yellow, or pink blooms that open in the morning and close by afternoon. It’s easy to see why people plant them intentionally in backyard water features or welcome them when they appear naturally. But there’s a critical difference between a few decorative lily pads at the edge of a pond and a full-scale infestation that’s quietly dismantling your aquatic ecosystem.

The Underground Problem No One Talks About

The real danger with lily pads isn’t what you see — it’s what you don’t. Beneath every floating leaf is a thick, fleshy rhizome buried in the sediment. These horizontal root-like structures grow outward continuously, branching as they go, anchoring new stems at regular intervals across the pond floor. A single plant can send rhizomes sprawling several feet in every direction within a single growing season.

This growth pattern is what makes lily pads so relentless. Even if you cut every visible leaf from the surface, those rhizomes remain fully alive and ready to push up new growth. The plant doesn’t need much encouragement — warm water temperatures, shallow depth, and nutrient-rich sediment are all it takes. And in older ponds where organic material has accumulated over years? That’s practically a lily pad paradise.

How Lily Pads Damage Your Pond or Lake

The ecological consequences of a lily pad takeover unfold in stages, and they compound on each other in ways that become increasingly difficult to reverse.

Surface Coverage Blocks Sunlight and Gas Exchange

When lily pad leaves blanket the water’s surface, they block the sunlight that submerged native aquatic plants depend on for photosynthesis. Without sunlight, those plants die off, removing a critical food source and habitat for fish, insects, and other aquatic life. The loss of native vegetation creates a vacuum that lily pads are only too happy to fill — further accelerating the takeover.

Just as important is the disruption of gas exchange at the water’s surface. Oxygen enters water through direct atmospheric contact, and carbon dioxide and other gases escape through the same interface. When that surface is covered by a dense mat of lily pads, this exchange is severely restricted. Dissolved oxygen levels can plummet — particularly overnight when aquatic plants stop photosynthesizing and begin consuming oxygen instead. Fish kills during the warmer months are a direct consequence of this oxygen depletion, and we see it happen with alarming regularity in heavily infested water bodies.

Nutrient Cycling Goes Off the Rails

Lily pads are efficient nutrient absorbers, pulling nitrogen and phosphorus from the water column and sediment. In small amounts, this is actually beneficial — they act like a filtration system. But in large colonies, they monopolize nutrients in a way that throws the entire ecosystem out of balance. When lily pads die off seasonally, that stored organic material sinks and decomposes on the pond floor.

Decomposition consumes oxygen and releases nutrients back into the sediment, fueling the next generation of growth. Over time, this cycle increases the organic muck at the bottom of the pond — reducing depth, accelerating sediment accumulation, and creating the nutrient-dense environment that lily pads and algae thrive in. What begins as an aesthetic annoyance can, over years, fundamentally compromise the long-term viability of your water body.

Wildlife Habitat Becomes Unbalanced

Lily pads do provide some ecological value in moderation — shade for fish, surfaces for insects, and cover for frogs and waterfowl. But an overgrown colony eliminates the open water that waterfowl need for landing, disrupts the thermal layering that fish use to regulate body temperature, and reduces the diversity of aquatic vegetation that supports a healthy food web. The biodiversity of a pond under lily pad domination tends to narrow sharply over time, leaving you with far fewer species of fish, insects, and plants than a well-balanced water body would support.

Access and Usability Take a Hit

Beyond the ecological damage, there’s the practical reality: a pond or lake choked with lily pads is largely unusable. Boating becomes difficult as stems wrap around propellers and the sheer density of growth slows navigation. Fishing access is blocked off from large portions of the water. Swimming becomes unappealing and potentially hazardous. Shoreline aesthetics — and with them, property values — decline noticeably.

These aren’t minor inconveniences. For HOA communities, lakefront homeowners, or anyone who has invested in waterfront property, an unchecked lily pad infestation represents a genuine threat to what they’ve worked to protect.

Identifying the Severity of Your Infestation

Not all lily pad situations are equal. A modest ring of growth along a pond’s shallow edge is a very different problem than a colony that’s carpeted 60 or 70 percent of the surface. Understanding where your infestation falls on that spectrum is the first step toward choosing the right approach.

Early-Stage Growth

If lily pads are covering less than 20 percent of your water body’s surface and are concentrated along the shallow margins, you’re likely dealing with early-stage growth. At this point, the rhizome network is not yet extensive, and targeted removal is both feasible and far less costly. The window for catching an infestation early is short — lily pad colonies can double in coverage quickly once conditions are favorable — so don’t wait for the situation to worsen.

Moderate Infestation

Coverage between 20 and 50 percent of the surface indicates an established infestation with a substantial rhizome network already in place. At this stage, a combination of methods will typically be needed, and any treatment plan must account for the root system, not just the visible surface growth. Attempting to address this with manual removal alone is rarely effective and often exhausting.

Severe Infestation

When more than half of your water body’s surface is covered — or when lily pads have consolidated into a dense mat that’s visibly altered the water’s appearance and usability — you’re dealing with a severe infestation. These situations require professional-grade intervention. The rhizome network is extensive, the sediment likely contains a reservoir of viable seeds and root fragments, and the treatment process will span multiple visits across more than one growing season.

Control Methods: What Works and What Doesn’t

There’s no shortage of advice on the internet about how to kill lily pads. Pond rakes, scissors, Roundup in a spray bottle from a boat — people try everything. Here’s a clear-eyed look at the actual options, their limitations, and where professional involvement becomes not just helpful but necessary.

Manual Removal

For very small, newly established patches, manual removal is a legitimate option. Using a pond rake or aquatic cutting shears, you can remove visible pads and attempt to pull or dig up the underlying rhizomes. This approach works best in shallow water with loose sediment where the root system is still relatively compact.

The catch is that manual removal requires consistency. A single session will not eliminate the rhizome network. Regrowth is virtually guaranteed unless you return repeatedly throughout the season, each time targeting new shoots before they can establish. It’s labor-intensive, wet work — and for any infestation beyond the earliest stage, it simply can’t keep pace with the plant’s regrowth capacity.

Aquatic Herbicide Applications

Herbicide treatment is one of the most effective tools available for controlling established lily pad infestations. Active ingredients with proven efficacy include 2,4-D, triclopyr, fluridone, glyphosate (aquatic-labeled formulations), and imazamox. Each has different modes of action, application timing considerations, and appropriate use contexts.

A few things matter enormously here. First, any herbicide used in a water body must be specifically labeled for aquatic use — standard agricultural or lawn formulations are not appropriate and may cause significant harm to fish and other aquatic life. Second, water temperature, application timing, and treatment area must be carefully managed. Treating more than a third of a water body at one time can cause a rapid die-off that depletes dissolved oxygen and triggers a fish kill. Third, in Maryland and across the Mid-Atlantic, herbicide applications in public and semi-public waterways require permits and must comply with Maryland Department of the Environment regulations.

This is precisely where DIY approaches frequently go wrong — not because the intent is bad, but because the technical and regulatory requirements are genuinely complex.

Mechanical Harvesting

Mechanical harvesting is the method Legacy Waters relies on most heavily for moderate to severe infestations. Specialized watercraft equipped with cutting blades and conveyor systems cut invasive plants below the waterline and collect the biomass directly on board. The harvested material is then transported off-site entirely, removing not just the visible plants but the nutrient load they represent.

This approach has significant advantages. It produces immediate, visible results without introducing chemicals into the water. It’s effective across large surface areas that would be impossible to address manually. And by removing the harvested biomass from the water body rather than leaving it to decompose, it interrupts the nutrient cycling that fuels future growth. Our equipment can reach invasive vegetation up to six feet below the surface — well beyond what most lily pad rhizomes extend.

Drawdown and Sediment Management

In some situations — particularly where lily pads have persisted for many years and the sediment is heavily colonized by rhizomes and seeds — a more comprehensive intervention is warranted. Lowering the water level to expose the pond floor during freezing winter months can kill rhizomes through desiccation and freeze cycles. In extreme cases, dredging to remove the nutrient-laden muck from the pond floor eliminates the substrate that supports regrowth and restores lost pond depth simultaneously.

At Legacy Waters, we offer hydraulic dredging as part of an integrated restoration approach for water bodies where lily pads and sediment accumulation have combined into a compounding problem. Addressing only the vegetation without dealing with the sediment is like treating symptoms without addressing the underlying condition.

Why Professional Removal Makes the Difference

The reason lily pad infestations spiral out of control so often is that they’re treated as a maintenance problem when they’re actually an ecological crisis. Cutting pads or spraying them down once a summer gives the rhizome network exactly the conditions it needs to spread — disturbance without elimination.

Effective lily pad management requires an integrated strategy: accurate assessment of the rhizome network’s extent, selection of appropriate removal methods for the infestation’s severity, timing treatments to align with the plant’s growth cycle, compliance with state regulations, and follow-up monitoring to address regrowth before it reestablishes.

Legacy Waters brings professional expertise, permitted operations, and the right equipment to every project. Our team has worked across Maryland’s diverse waterways — from private residential ponds to HOA lakes to golf course water features — and we understand how local conditions influence both the nature of the infestation and the most effective path to restoration. We handle permitting, execution, and post-treatment monitoring, so our clients get results they can actually enjoy rather than a temporary fix that unravels by mid-summer.

If lily pads have started claiming your water, the best time to act was last season. The second-best time is right now.

What Your Wondering about Lily Pads

Are lily pads invasive, or are they native plants?

This depends on the species. Some water lily varieties, like Nymphaea odorata (fragrant water lily), are native to the eastern United States and naturally occur in many Mid-Atlantic waterways. However, even native species can become invasive in terms of behavior — particularly in nutrient-enriched or disturbed water bodies where they face little ecological competition. Non-native cultivars introduced through ornamental planting can spread into natural waterways and establish truly invasive populations. The distinction between “native” and “invasive” matters less than the ecological impact: when lily pads cover more than 20 percent of a pond or lake’s surface and are displacing native vegetation, the situation warrants active management regardless of species origin.

Can I remove lily pads myself without professional help?

For very small patches in early-stage growth, manual removal using a pond rake or aquatic cutting shears can be effective if done consistently throughout the growing season. However, DIY removal has real limitations. It cannot reach deep rhizomes effectively, physical removal alone rarely keeps pace with regrowth in established infestations, and any herbicide application in a water body requires careful product selection, proper timing, and — in many jurisdictions — permits and regulatory compliance. In Maryland, professional aquatic herbicide applications must comply with Maryland Department of the Environment guidelines. Attempting to manage a moderate or severe infestation without professional support often results in temporary cosmetic improvement followed by more aggressive regrowth.

How long does lily pad removal take to show results?

The timeline depends on the treatment method and the severity of the infestation. Mechanical harvesting produces immediate visible results — surface coverage is reduced on the same day work is performed. Herbicide treatments typically show visible die-off within one to two weeks of application, though the full treatment may require multiple applications across a season. Completely eliminating an established lily pad infestation — including the underlying rhizome network — generally takes more than one growing season. Expect an initial treatment period followed by monitoring and targeted follow-up treatments to address regrowth from surviving rhizomes or dormant seeds in the sediment.

Will removing lily pads harm the fish in my pond or lake?

When removal is handled correctly, it poses no threat to fish populations — in fact, restoring appropriate dissolved oxygen levels and open-water habitat actively benefits fish health. The risk to fish during removal comes primarily from two scenarios: rapid large-scale herbicide treatment that triggers a mass die-off and oxygen crash, and poorly executed manual removal that leaves large volumes of decomposing plant material in the water. Legacy Waters avoids both by treating no more than a third of a water body at a time during chemical treatments and by mechanically removing harvested biomass from the site entirely.

What is the best time of year to treat lily pads?

Timing varies by treatment method. Aquatic herbicides are most effective when water temperatures have reached at least 60°F and plants are actively growing — typically late spring through early summer. Systemic herbicides like glyphosate can also be applied effectively in late summer when the plant is translocating nutrients downward into the rhizomes, potentially delivering more thorough root kill. Mechanical harvesting can be performed throughout the growing season and is most impactful when timed to interrupt the plant’s growth cycle before it can set new rhizomes. For drawdown-based control, late fall through winter is the target window, with the goal of exposing rhizomes to hard freezes. A professional assessment of your specific water body and infestation stage is the most reliable way to determine optimal treatment timing.