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Best Aquatic Herbicides

Ponds and other freshwater sources can be a hotbed of invasive aquatic flora. You need not worry though since there is a solution to keep these plants from wreaking havoc on your pond’s ecosystem. Aquatic herbicides, if used properly, can help prevent this problem from worsening. Here are some facts that you need to know about the item plus a list of top product picks.

Buyers Guide

  1. Are aquatic herbicides really safe?

    Answer: Aquatic herbicides are strictly monitored and evaluated by the EPA or Environmental Protection Agency. Thus, this makes the product safe for non-target flora and fauna when applied by a certified applicator following the steps mentioned in the product’s label. Today’s batch of herbicides, regulated since 2003, are single-site plant enzyme inhibitors which are used at significantly lower doses.

    Keep in mind that as long as you use the appropriate herbicide in accordance with the instructions accompanying the product, it will not threaten the lives of non-target plants, animals, birds, pets, frogs or any wildlife in the area.

  2. When should I apply aquatic herbicides?

    Answer: Aquatic herbicides must be applied whenever the weeds are growing aggressively. Invasive aquatic plants that have matured make herbicides less effective.

  3. Can a whole pond be treated with an aquatic herbicide?

    Answer: You will get better results if you treat a whole pond. This step prevents the possibility that untreated spots in the pond will eat into the spots that were treated with the herbicide. Treating a whole pond though must be performed in sections—this means you need to treat a third to a half one by one and at least allow 5-7 days between each treatment, in order to minimize oxygen depletion caused by dead weed decomposition.

  4. How long do these treatments last?

    Answer: The length of the treatment’s effectivity will be based on the product that was used, the conditions in the area and the plants that were targeted. Usually, systemic herbicides offer more long-term benefits compared to contact herbicide types.

Our Top Picks


Crystal Blue Copper Sulfate Algaecide

  • 99% Copper Sulfate Pentahydrate
  • Stops majority of algae species
  • 5 lbs. granular copper sulfate
  • Safe to use

The Crystal Blue Copper Sulfate Algaecide is for ponds ridden with invasive string algae and other types of dangerous algae species. This herbicide is recommended as treatment on algae that has been developing in waters with temperatures more than 60-degrees F. Copper algae is safe for most fish species in general however this is not recommended for garden ponds with goldfish or koi fish. Check out this product in this review.


SePRO Sonar RTU Aquatic Weed Herbicide

  • Long-term effects
  • Can stop duckweed
  • Does not require mixing
  • Easy to apply

The SePro Sonar RTU Aquatic Weed Herbicide is an easy to apply DIY treatment for your pond. It is capable of stopping invasive pond flora species like duckweed, coontail, hydrilla and milfoil. The treatment program includes 3 treatments for the initial application, for Day 21 and Day 42. There’s no mixing required for this solution, you won’t even need a sprayer for this; all you need to do is apply the solution straight to the water from the shore. Get more insight on this product thru this review.


Clipper Aquatic Herbicide

  • Quick aquatic plant control
  • Treats most weeds
  • Dissolves fast
  • Mixes effortlessly

The Clipper Aquatic Herbicide is designed to destroy problematic weed invasion in your pond. It delivers when it comes to preventing maturity of aquatic plants like watermilfoil, duckweed and more related flora. It has a formulation of fast-dissolving granules which are a breeze to mix in the water. For application, it can be mixed with water and a Treatment Booster in a spray equipment. It will not build up in the pond after application as well. Learn more about it on this product video.


VPG Hi-Yield Killzall Aquatic Herbicide

  • 53.8% Glyphosate
  • Non-selective aquatic plant herbicide
  • One quart covers up to an acre
  • Mixes easily with water

The Hi-Yield Killzall Concentrate Aquatic Herbicide is recommended for stopping nuisances that might disturb healthy aquatic or non-crop ecosystems. It dissolves and mixes effortlessly with water. You can use this with a spray applicator. It is capable of ridding areas of annual and perennial grasses, broadleaf weeds plus aquatic nuisances like cattails, water lettuce and water hyacinths. Get more in-depth opinions on this product in this video.


Weed Slayer Organic Herbicide

  • Controls weed and grass organically
  • Safe and natural alternative to glyphosate
  • WSDA-certified for organic use
  • Kills at the root

The Weed Slayer is designed to be a safer alternative for herbicides with glyphosate. It works in controlling tenacious weeds and grass. It has a formula composed of a two-part broad-spectrum organic herbicide, with one portion crafted from a plant-based essential oil of clove called Eugenol and one portion a distinctive patented bio surfactant which assists in transferring the herbicide into the target. For a more in-depth review, please check out this Weed Slayer video.

Keeping a pond requires effort. If you want a healthy pond at all times, you need to make sure that the underwater ecosystem is healthy. There are steps in which you can guarantee a healthier pond; you need to make sure that it has the right pump and related equipment for better water circulation and filtration.

But what about the control of aquatic plants? No need to worry since as seen on the top product picks above, we have a solution to curb weed and algae nuisances. The list in this guide will help you determine which among the products cater to your pond’s condition.