Eurasian milfoil is a submerged aquatic weed that forms dense mats in lakes, ponds, rivers, and irrigation canals. It spreads through stem fragments that root in new areas, and it can dominate a waterbody within a few seasons. Because it grows under water, control requires aquatic-approved herbicides, not terrestrial products.
Effective Eurasian milfoil control depends on the size of the infestation, water depth, water flow, and whether the waterbody is used for drinking, irrigation, or recreation. Whole-lake treatments work for large infestations, while spot treatments and bottom barriers are better for small patches. Timing applications for early summer, when the plant is actively growing, delivers the best results.
Eurasian milfoil is often found alongside native aquatic plants and fish habitat, so product selection must account for non-target species and water-use restrictions. Only aquatic-labeled herbicides can be legally applied to water, and many products carry strict restrictions on irrigation, swimming, and drinking water use after treatment.
In this guide, we review the best herbicides for Eurasian milfoil by examining aquatic-approved products, application methods, and safe-use practices for long-term control.
Best Herbicide For Eurasian Milfoil: Top 15 Options
1. Fluridone – Best Overall Herbicide For Eurasian Milfoil
Fluridone is the best overall herbicide for Eurasian milfoil because it is a systemic, whole-lake treatment that kills the plant slowly and completely, including the roots. It is absorbed through the leaves and stems and translocated throughout the plant, disrupting photosynthesis and pigment production. It is one of the most widely used aquatic herbicides in North America.
- No Mixing, No Spray Equipment, or Boat needed
- The most simple DIY systemic herbicide you can buy, just pour in the right dose directly into the pond
Fluridone is labeled for lakes, ponds, and irrigation canals to control Eurasian milfoil and other submerged aquatic weeds. It works best when applied in early summer when the plant is actively growing, and it requires several weeks of contact time to be effective. It is typically applied by licensed aquatic applicators.
This product has no soil residual activity and breaks down in sunlight, so it does not persist in sediment. However, it can affect non-target native plants if applied at high rates, so careful dosing is essential for protecting beneficial species.
- Systemic whole-lake control
- Kills roots and stems
- No soil residual
- Effective on large infestations
- Long contact time
- Widely used in lakes
- Trusted by aquatic managers
- Requires licensed applicator
- Slow results
- Can affect native plants
2. 2,4-D – Best Selective Herbicide For Eurasian Milfoil
2,4-D is a selective aquatic herbicide that controls Eurasian milfoil and other broadleaf aquatic plants without harming most grasses or sedges. It is a synthetic auxin that causes uncontrolled cell division and twisting. It is absorbed through leaves and stems and translocated throughout the plant.
- BROADLEAF WEED ELIMINATOR: Our 2,4-D Amine herbicide effectively tackles a wide range of tough broadleaf weeds, including Pigweed, Thistle, Ragweed, and more. Keep your pastures, lawns, landscape, and aquatic sites clean and thriving with just one solution
- FARM-GRADE WEED CONTROL: Formulated with 47.2% active ingredient, the grass weed killer delivers superior results with every application. Achieve professional-grade weed control for a variety of environments, including farms and industrial areas
2,4-D is labeled for lakes, ponds, and irrigation canals to control Eurasian milfoil and other broadleaf aquatic weeds. It works best when applied in early summer when the plant is actively growing. It is available in liquid and granular formulations for different application methods.
This product has limited soil residual activity, so it does not prevent new growth from fragments. It requires careful application to protect desirable native plants and comply with water-use restrictions.
- Selective for broadleaf weeds
- Safe for most grasses and sedges
- Absorbed and translocated
- Liquid and granular options
- Works in lakes and ponds
- Fast-acting
- Trusted by aquatic managers
- Water-use restrictions
- Requires licensed applicator
- Can affect native broadleaf plants
3. Triclopyr – Best For Milfoil In Flowing Water
Triclopyr is a selective aquatic herbicide that controls Eurasian milfoil and other broadleaf aquatic plants in lakes, rivers, and canals. It is absorbed through leaves and stems and translocated to the roots, killing the entire plant. It is available in aquatic-labeled formulations for different application methods.
- REVIVE FORESTS AND PASTURES: Triclopyr 4 Herbicide targets & controls woody plants, broadleaf weeds, & brush, making it ideal for restoring pastures and managing unwanted vegetation in forests, rangelands, and industrial sites without harming grasses
- YEAR-ROUND APPLICATION FLEXIBILITY: With flexible application options throughout the year, this broadleaf herbicide offers versatility for a wide range of conditions. Its ester formulation allows for effective absorption through leaves and roots
Triclopyr is labeled for lakes, ponds, rivers, and irrigation canals to control Eurasian milfoil and other broadleaf aquatic weeds. It works best when applied in early summer when the plant is actively growing. It is effective in both still and flowing water, making it a good option for rivers and canals.
This product has moderate soil residual activity in some formulations. It can injure desirable broadleaf aquatic plants if applied carelessly, so careful targeting is essential in mixed plant communities.
- Works in flowing water
- Selective for broadleaf plants
- Safe for most grasses
- Absorbed and translocated
- Effective on established plants
- Widely used in rivers and canals
- Trusted by aquatic managers
- Some soil residual
- Water-use restrictions
- Requires licensed applicator
4. Endothall – Best Fast-Acting Contact Herbicide
Endothall is a fast-acting contact herbicide that controls Eurasian milfoil and other submerged aquatic plants. It is absorbed through leaves and stems and disrupts cell membranes, causing rapid wilting and collapse of treated plants. It is available in liquid and granular formulations.
- Hydrothol 191 Granular: Hydrothol Granular uses 11.2% concentrated Mono (N, N-dimethylalkylamine) Salt of Endothall, and continues to be a highly effective herbicide/algaecide solution for a variety of aquatic nuisances. Be sure to apply this product when weeds and algae are actively growing. Susceptibility of algae may vary due to subspecies, strains or environmental conditions. There is also a liquid option but this is sold to commercial applicators only. Check permitting requirements in your area prior to applying.
- EFFECTIVE HERBICIDE AND ALGAECIDE: Hydrothol Aquatic Herbicide and Algaecide has been successfully used for over 30 years. Today Hydrothol is used primarily as an algaecide. Hydrothol is the only registered broad spectrum organic aquatic algaecide available today. Hydrothol can be used in combination, in rotation or as an alternative to copper for control of algae.
Endothall is labeled for lakes, ponds, and irrigation canals to control Eurasian milfoil and other submerged aquatic weeds. It works best when applied in early summer when the plant is actively growing. It acts within days of application, making it a good option when fast results are needed.
This product has limited soil residual activity and does not kill roots as completely as systemic herbicides. It requires careful application to protect desirable native plants and comply with water-use restrictions.
- Fast contact action
- Liquid and granular options
- Effective on submerged plants
- Works in lakes and ponds
- Reduces biomass quickly
- Widely used
- Trusted by aquatic managers
- Weak on root kill
- Water-use restrictions
- Requires licensed applicator
5. Diquat – Best For Fast Burndown Of Milfoil
Diquat is a fast-acting contact herbicide that rapidly desiccates Eurasian milfoil and other submerged aquatic plants. It is absorbed through leaves and disrupts cell membranes, causing wilting and collapse within days. It has no soil residual activity and does not translocate to roots.
- FAST-ACTING FORMULA: See visible results in just 1-2 days with our weed killer; It's a quick solution for stubborn weeds like chickweed, poison ivy, and more
- VERSATILE APPLICATIONS: Perfect for both water and land, tackle weeds in ponds, lakes, greenhouses, nurseries, and landscapes with one versatile product
Diquat is labeled for lakes, ponds, and irrigation canals to control Eurasian milfoil and other submerged aquatic weeds. It works best when applied in early summer when the plant is actively growing. It acts within days of application, making it a good option when quick top-kill is needed.
This product has no soil residual activity, so it does not prevent new growth from fragments. It requires careful application to protect desirable native plants and comply with water-use restrictions.
- Fast contact action
- No soil residual
- Effective on submerged plants
- Works in lakes and ponds
- Reduces biomass quickly
- Widely available
- Trusted by aquatic managers
- No root kill
- Water-use restrictions
- Requires licensed applicator
6. Copper Complexes – Best For Algae And Milfoil Control
Copper complexes are broad-spectrum aquatic herbicides that control Eurasian milfoil, algae, and other aquatic weeds. They are absorbed through plant tissues and disrupt cell membranes and enzyme function. They are available in liquid and granular formulations for different application methods.
- FAST-ACTING ALGAE CONTROL: This pond algaecide works quickly to eliminate planktonic algae within 24-48 hours and filamentous algae in just 3-4 days, restoring clear water fast so you can enjoy your lakes, ponds, or irrigation systems without waiting
- BROAD-SPECTRUM WEED SOLUTION: Keep your water bodies healthy and weed-free with ease, as our algaecide for pond targets a wide range of algae types and the invasive Hydrilla plant, delivering reliable control with copper concentrations as low as 0.4 PPM
Copper complexes are labeled for lakes, ponds, and irrigation canals to control Eurasian milfoil and other aquatic weeds. They work best when applied in early summer when the plant is actively growing. They act within days of application, making them a good option when fast results are needed.
These products have some soil residual activity and can accumulate in sediment over time. They require careful application to protect desirable native plants and comply with water-use restrictions.
- Controls milfoil and algae
- Fast-acting
- Liquid and granular options
- Works in lakes and ponds
- Widely used
- Affordable
- Trusted by aquatic managers
- Can accumulate in sediment
- Water-use restrictions
- Requires licensed applicator
7. Imazamox – Best For Selective Milfoil Control
Imazamox is a selective aquatic herbicide that controls Eurasian milfoil and other broadleaf aquatic plants without harming most grasses and sedges. It is absorbed through leaves and roots and translocated throughout the plant. It is available in aquatic-labeled formulations.
- PRECISION WEED TARGETING: This weed and grass killer provides exceptional, selective weed control in aquatic and terrestrial environments. It targets tough species like Water Hyacinth, and Ryegrass, ensuring a cleaner, healthier landscape
- ROOT-TO-TIP WEED CONTROL: Enjoy long-lasting weed control with pre- and post-emergent activity, as our pre-emergent weed control combats stubborn weeds from the roots up, offering effective management for newly sprouted and established weeds
Imazamox is labeled for lakes, ponds, and irrigation canals to control Eurasian milfoil and other broadleaf aquatic weeds. It works best when applied in early summer when the plant is actively growing. It is often tank-mixed with other aquatic herbicides for broader spectrum control.
This product has moderate soil residual activity that can affect sensitive aquatic plants for months. It requires careful application to protect desirable native plants and comply with water-use restrictions.
- Selective for broadleaf plants
- Safe for most grasses
- Absorbed and translocated
- Works in lakes and ponds
- Moderate soil residual
- Reduces repeat applications
- Trusted by aquatic managers
- Some soil residual
- Water-use restrictions
- Requires licensed applicator
8. Bispyribac-Sodium – Best For Selective Milfoil Control
Bispyribac-sodium is a selective aquatic herbicide that controls Eurasian milfoil and other broadleaf aquatic plants without harming most grasses and sedges. It is absorbed through leaves and roots and translocated throughout the plant. It is available in aquatic-labeled formulations.
- Glyphosate - 53.8%
- Read product label for information and product use before using.
Bispyribac-sodium is labeled for lakes, ponds, and irrigation canals to control Eurasian milfoil and other broadleaf aquatic weeds. It works best when applied in early summer when the plant is actively growing. It is often tank-mixed with other aquatic herbicides for broader spectrum control.
This product has moderate soil residual activity that can affect sensitive aquatic plants for months. It requires careful application to protect desirable native plants and comply with water-use restrictions.
- Selective for broadleaf plants
- Safe for most grasses
- Absorbed and translocated
- Works in lakes and ponds
- Moderate soil residual
- Reduces repeat applications
- Trusted by aquatic managers
- Some soil residual
- Water-use restrictions
- Requires licensed applicator
9. Penoxsulam – Best For Low-Rate Milfoil Control
Penoxsulam is a selective aquatic herbicide that controls Eurasian milfoil and other broadleaf aquatic plants at low application rates. It is absorbed through leaves and roots and translocated throughout the plant. It is available in aquatic-labeled formulations.
- INSTANT WEED CONTROL: Expect visible results within hours, as hydrilla killer starts working immediately on contact with green plant tissue, making it an ideal solution when fast, effective weed control is needed with minimal downtime
- GLYPHOSATE-FREE POWER: This non-selective aquatic herbicide for ponds provides broad-spectrum control without using glyphosate. It works quickly to kill a wide range of weeds and is ideal for those looking for an efficient and fast-acting substitute
Penoxsulam is labeled for lakes, ponds, and irrigation canals to control Eurasian milfoil and other broadleaf aquatic weeds. It works best when applied in early summer when the plant is actively growing. It is often tank-mixed with other aquatic herbicides for broader spectrum control.
This product has moderate soil residual activity that can affect sensitive aquatic plants for months. It requires careful application to protect desirable native plants and comply with water-use restrictions.
- Low application rates
- Selective for broadleaf plants
- Safe for most grasses
- Absorbed and translocated
- Works in lakes and ponds
- Reduces repeat applications
- Trusted by aquatic managers
- Some soil residual
- Water-use restrictions
- Requires licensed applicator
10. Flumioxazin – Best For Fast Contact Control
Flumioxazin is a fast-acting contact herbicide that controls Eurasian milfoil and other submerged aquatic plants. It is absorbed through leaves and disrupts cell membranes, causing rapid wilting and collapse of treated plants. It has limited soil residual activity.
- THE PRO CHOICE FOR SEASON-LONG WEED CONTROL: Semera 51.0% WDG contains 51% flumioxazin; the same active ingredient as the Leading Brand, the herbicide pros trust for season-long weed control.
- AQUATIC WEED CONTROL: Semera 51.0% WDG is a fast-acting contact herbicide that controls selected submersed, emergent and floating aquatic weeds. Controls Duckweed, Alligator Weed, Coontail, Frog's-bit, Hydrilla, Pondweed, Water Fern, Water Lettuce, Watermilfoil.
Flumioxazin is labeled for lakes, ponds, and irrigation canals to control Eurasian milfoil and other submerged aquatic weeds. It works best when applied in early summer when the plant is actively growing. It acts within days of application, making it a good option when fast results are needed.
This product has limited soil residual activity and does not kill roots as completely as systemic herbicides. It requires careful application to protect desirable native plants and comply with water-use restrictions.
- Fast contact action
- Limited soil residual
- Effective on submerged plants
- Works in lakes and ponds
- Reduces biomass quickly
- Widely available
- Trusted by aquatic managers
- Weak on root kill
- Water-use restrictions
- Requires licensed applicator
11. Carfentrazone-Ethyl – Best For Selective Contact Control
Carfentrazone-ethyl is a selective contact herbicide that controls Eurasian milfoil and other broadleaf aquatic plants. It is absorbed through leaves and disrupts cell membranes, causing rapid wilting and collapse of treated plants. It has limited soil residual activity.
- Provides ultra-fast weed control
- Visible results in just 24 hours
Carfentrazone-ethyl is labeled for lakes, ponds, and irrigation canals to control Eurasian milfoil and other broadleaf aquatic weeds. It works best when applied in early summer when the plant is actively growing. It is often tank-mixed with systemic herbicides for longer control.
This product has limited soil residual activity and does not kill roots as completely as systemic herbicides. It requires careful application to protect desirable native plants and comply with water-use restrictions.
- Fast contact action
- Selective for broadleaf plants
- Limited soil residual
- Works in lakes and ponds
- Tank-mix flexibility
- Widely available
- Trusted by aquatic managers
- Weak on root kill
- Water-use restrictions
- Requires licensed applicator
12. Diquat + Endothall – Best Combination For Fast Control
Diquat combined with endothall provides fast contact control of Eurasian milfoil and other submerged aquatic plants. Both ingredients disrupt cell membranes and cause rapid wilting and collapse of treated plants. The combination delivers faster top-kill than either product alone.
- INSTANT WEED CONTROL: Expect visible results within hours, as hydrilla killer starts working immediately on contact with green plant tissue, making it an ideal solution when fast, effective weed control is needed with minimal downtime
- GLYPHOSATE-FREE POWER: This non-selective aquatic herbicide for ponds provides broad-spectrum control without using glyphosate. It works quickly to kill a wide range of weeds and is ideal for those looking for an efficient and fast-acting substitute
Diquat plus endothall is labeled for lakes, ponds, and irrigation canals to control Eurasian milfoil and other submerged aquatic weeds. It works best when applied in early summer when the plant is actively growing. It acts within days of application, making it a good option when quick top-kill is needed.
This combination has limited soil residual activity and does not kill roots as completely as systemic herbicides. It requires careful application to protect desirable native plants and comply with water-use restrictions.
- Fast contact action
- Broad-spectrum control
- Limited soil residual
- Works in lakes and ponds
- Reduces biomass quickly
- Widely used
- Trusted by aquatic managers
- Weak on root kill
- Water-use restrictions
- Requires licensed applicator
13. Fluridone + 2,4-D – Best Combination For Long-Term Control
Fluridone combined with 2,4-D provides systemic, long-term control of Eurasian milfoil and other broadleaf aquatic plants. Fluridone kills the roots and stems slowly, while 2,4-D provides faster top-kill and broader spectrum activity. The combination delivers more complete control than either product alone.
- BROADLEAF WEED ELIMINATOR: Our 2,4-D Amine herbicide effectively tackles a wide range of tough broadleaf weeds, including Pigweed, Thistle, Ragweed, and more. Keep your pastures, lawns, landscape, and aquatic sites clean and thriving with just one solution
- FARM-GRADE WEED CONTROL: Formulated with 47.2% active ingredient, the grass weed killer delivers superior results with every application. Achieve professional-grade weed control for a variety of environments, including farms and industrial areas
Fluridone plus 2,4-D is labeled for lakes, ponds, and irrigation canals to control Eurasian milfoil and other aquatic weeds. It works best when applied in early summer when the plant is actively growing. It requires several weeks of contact time to be effective.
This combination has limited soil residual activity and breaks down in sunlight. It requires careful application to protect desirable native plants and comply with water-use restrictions.
- Systemic root kill
- Broad-spectrum control
- Fast top-kill
- Long-term control
- Works in lakes and ponds
- Reduces repeat applications
- Trusted by aquatic managers
- Water-use restrictions
- Requires licensed applicator
- Can affect native plants
14. Bottom Barriers – Best Non-Chemical Alternative
Bottom barriers are non-chemical control methods that block sunlight and prevent Eurasian milfoil from growing. They are installed on the lake or pond bottom and remain in place for one or more growing seasons. They work best on small patches and around docks and swimming areas.
- How It Works: The Lake Bottom Blanket reduces sunlight exposure to the lake floor, which helps limit the growth of underwater vegetation. Simply position the blanket over the area you’d like to manage. It works only on the plants it covers, while allowing fish and other aquatic life to move freely underneath.
- What's Included in the Box: (1) Our Patented Lake Bottom Blanket with weight channels (un-weighted) (2) Installation ropes, Rebar End Caps and Warning Buoy (3) Instructions and QR Code to view videos on your phone or computer.
Bottom barriers are installed on the lake bottom to control Eurasian milfoil and other submerged aquatic weeds. They work best when installed in early spring before the plant begins growing. They block sunlight and prevent photosynthesis, killing the plant beneath the barrier.
These barriers have no soil residual activity and do not affect water quality. They require careful installation to prevent damage to fish habitat and to comply with local regulations.
- No herbicides required
- Safe for water quality
- Effective on small patches
- Works around docks
- Long-lasting control
- Environmentally friendly
- Trusted by lake managers
- Labor intensive
- Expensive for large areas
- Can damage fish habitat
15. Hand Pulling And Diver-Assisted Removal – Best For Small Patches
Hand pulling and diver-assisted removal are non-chemical control methods that remove Eurasian milfoil by hand or with the help of divers. They are highly selective and remove the entire plant, including the roots, when performed carefully. They work best on small, isolated patches before the plant spreads.
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Hand pulling and diver-assisted removal are used in lakes, ponds, and sensitive natural areas to control Eurasian milfoil. They work best when performed in early summer before the plant fragments and spreads. They remove the plant without chemicals and protect native species.
These methods have no soil residual activity and do not affect water quality. They require trained divers and careful handling to prevent fragmentation that spreads the plant to new areas.
- No herbicides required
- Selective for target plant
- Safe for native species
- Works in sensitive areas
- Immediate results
- Environmentally friendly
- Trusted by lake managers
- Labor intensive
- Only for small patches
- Requires trained divers
Tips For Controlling Eurasian Milfoil With Herbicides
- Confirm the plant first: Confirm that the plant is Eurasian milfoil and not a native milfoil species before treatment, since native milfoils are beneficial in many waterbodies.
- Use aquatic-labeled herbicides only: Terrestrial herbicides are not legal for use in water. Use only products specifically labeled for aquatic use.
- Hire a licensed applicator: Most aquatic herbicides require a licensed applicator and permits. Contact your state or provincial environmental agency before treatment.
- Treat before fragmentation: Apply herbicides in early summer before the plant fragments and spreads to new areas.
- Watch water-use restrictions: Most aquatic herbicides carry restrictions on irrigation, swimming, and drinking water use after treatment. Check the label carefully.
- Combine methods: Combining herbicides with bottom barriers, diver-assisted removal, and nutrient management delivers the most reliable long-term control.
- Monitor and re-treat: Eurasian milfoil regrows from stem fragments and seeds. Scout treated areas several times per season and re-treat new growth while it is small.
Best Herbicide For Eurasian Milfoil FAQ’S
1. What is the best herbicide for Eurasian milfoil?
Fluridone is the best overall herbicide for Eurasian milfoil because it is systemic and kills the roots and stems. 2,4-D, triclopyr, and endothall are also effective, and the best choice depends on the waterbody and use restrictions.
2. Will vinegar kill Eurasian milfoil?
Vinegar does not kill Eurasian milfoil in water because it is diluted before it can affect the plant. Aquatic-approved herbicides or non-chemical methods like bottom barriers and diver-assisted removal are the correct options.
3. How do I kill Eurasian milfoil without harming fish?
Use aquatic-approved herbicides at the labeled rate and follow water-use restrictions. Combining herbicides with bottom barriers and nutrient management protects fish habitat while controlling the plant.
4. When is the best time to treat Eurasian milfoil?
Early summer is the best time to treat Eurasian milfoil because the plant is actively growing and moving energy to its roots. Treat before the plant fragments and spreads to new areas.
5. Does Eurasian milfoil come back after treatment?
Eurasian milfoil can regrow from stem fragments and seeds after a single treatment. Repeated applications over several seasons and combining methods are usually needed for complete control.
6. Is Eurasian milfoil dangerous?
Eurasian milfoil is not directly toxic to humans, but it forms dense mats that block swimming, boating, and fishing. It also harms native aquatic ecosystems by crowding out beneficial plants.
7. Do I need a permit to treat Eurasian milfoil?
Yes, most states and provinces require permits for aquatic herbicide applications. Contact your local environmental agency before treating any waterbody. Licensed applicators typically handle permits as part of the treatment process.
Conclusion
Fluridone is the best overall herbicide for Eurasian milfoil because it is systemic and kills the roots and stems. 2,4-D, triclopyr, and endothall follow closely as selective or fast-acting options for different waterbodies and use restrictions.
For long-term residual control, imazamox, bispyribac-sodium, and penoxsulam prevent new growth from establishing and reduce the need for repeat applications. Non-chemical methods like bottom barriers and diver-assisted removal are best for small patches and sensitive areas.
Effective Eurasian milfoil control requires aquatic-labeled products, licensed applicators, and strict compliance with water-use restrictions. Combining herbicides with nutrient management and non-chemical methods delivers the most reliable long-term control.
Start your Eurasian milfoil control program this season, confirm the plant before treatment, and plan for follow-up treatments each year. Consistent effort over several seasons protects water quality, native species, and recreational use.