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One of the battles we face as pond managers is the seemingly never-ending war on weeds and algae. Normally, we rail against algae blooms after a gully-washer of a thunderstorm adds 10 tons of nutrient leaden sediments into the pond, or an invasive aquatic plant like Eurasian Watermilfoil shows up, and you have to spend years and thousands of dollars to kill it dead.
It seems like a betrayal most heinous when one of our native plant friends becomes the biggest issue for our pond. Such can be the case with several of our native species, and unfortunately, American Pondweed is one of them…
(meme-arsenal.com)
If American pondweed is choking your pond, blocking your boat, or ruining the fishing…. You are not alone.
Many pond owners find themselves in a similar spot—battling Potamogeton nodosus, better known as American pondweed (or long-leafed pondweed). It starts as a beneficial plant, but when left unchecked, it can overrun your pond.
Here’s the twist: getting rid of it entirely can do more harm than good.
Potamageton nodosus is a native pondweed and can grow just about anywhere in the US and Canada. Its presence is most dense in the midwestern states and central provinces, but it can (and does) grow in a wide variety of aquatic environments and conditions.
American Pondweed (American PW) has two types of leaves, submerged and floating. Two-leaf forms are a cool feature of some pondweeds that adds to their ability to grow just about anywhere. This dual growth form not only makes American PW adaptable, but also a pain in the rear to control.
American PW is most commonly misidentified as Illinois Pondweed, which is understandable as they look a lot alike.
(backyardnature.net)
Alas, the plant we are discussing here (American PW) has the following characteristics:
The easiest way to ID American PW is by its leaves.
Submersed Leaves:
Thin
Oval-shaped
About 8 inches long
Approx - 1.3-1.5 inches wide
Floating leaves:
Leather-like texture
Long leaf stalks
Elliptical-shaped
Somewhat rounded at base
Approx - 4 inches long
Approx - 1.75 inches wide
American PW does have a rather un-noteworthy flower, and its stems are diagnostic, but you do not really need that level of scrutiny to ID American PW. Plus, any plant that is that close in resemblance to American PW is controlled the same way, so…… Looks like American Pondweed to me, let's proceed.
(inspiredpencil.com)
(invasive.org)
While American PW is native and not invasive, its rapid growth can lead to real issues. When overgrown, it creates thick mats that clog boat motors, paddles, and intakes. It disrupts the predator-prey balance by offering too much cover and can cause nighttime oxygen drops that stress or kill fish.
And let’s be honest—it’s not the prettiest sight when it takes over the shoreline.
Despite all that, American pondweed actually plays an important role in pond health. It supports aquatic biodiversity, improves water clarity by stabilizing sediment, and even helps reduce harmful algae blooms. It creates shade and cover and is generally a good plant to have in your pond. Like most everything else, too much of a good thing is a bad thing.
That’s why the goal isn’t to eliminate it entirely. It’s about balanced management.
Early action is key. Once pondweed spreads, it gets tougher—and more expensive—to control. Here's how you can restore balance without harming your pond:
For small patches, nothing beats physical effort. A weed razor or aquatic rake can help cut and pull pondweed directly. It’s time-consuming but ideal for precise control, especially near docks or swimming areas.
Triploid grass carp offer a natural solution. These sterile fish love munching on pondweed and won’t breed out of control. Always check your state regulations before stocking them—they often require a permit (or are illegal in some states).
In more serious cases, herbicides may be necessary. For spot treatments, Aquathol K or Super K works well. For broader, longer-term control, Fluridone (Sonar) is a great option. Diquat-based herbicides act fast but might require follow-up applications.
Just remember to use only aquatic-approved products and always follow label directions to prevent oxygen crashes and protect fish. Please consult with a professional pond manager to confirm plant ID and get guidance on dosage and delivery strategy. Handling concentrated herbicide must be done carefully and cautiously.
Stopping nutrient runoff is one of the most effective ways to reduce regrowth. Limit fertilizer use near your pond and redirect stormwater. Using pond dye in early spring can also help by reducing sunlight penetration, which slows weed growth. Sediment covers work great for pondweed control. There are weighted options on the market that smother aquatic plants in defined areas. These mats can be moved around after a month or two to gain and maintain good control in small areas.
Imagine Your Pond—Balanced and Clear
Picture boating without the drag. Fishing without the frustration. A shoreline that’s clean, inviting, and alive with healthy fish and wildlife. That’s what effective pondweed control can give you.
Start by assessing your pond. Ideally, aquatic vegetation should cover about 15–25% of your water body to support a healthy ecosystem without overwhelming it.
Choose the best method for your situation—manual, biological, or chemical—and follow up with a proactive plan to prevent future overgrowth.
American pondweed has a place in your pond. It’s not about wiping it out, but managing it wisely so both your ecosystem and your recreation thrive. Please contact us anytime at sales@midwestponds.com or drop us a line at 833-779-2837 to discuss your pond project and get the advice you need to make your pond a stellar aquatic resource that you can be proud of.
