You should never use Roundup to kill weeds in or around a pond. The surfactants in Roundup are extremely deadly to fish and other aquatic life. You may kill a few weeds near the pond, but you will also wipe out wildlife. Instead of Roundup, use an aquatic formulation of glyphosate (the same active ingredient in Roundup) mixed with a water-safe surfactant. This will allow you to kill pond weeds without harming fish and amphibians.
Why Can’t You Use Roundup for Pond Weeds?
Roundup should never be applied on or near pond weeds because certain ingredients in Roundup are deadly to aquatic animals. This study found that Roundup killed 96–100% of tadpoles within 3 weeks and 68–86% of juvenile amphibians in 24 hours. The damaging effects of Roundup on aquatic life cannot be overstated.
- Roundup sprayed on bodies of water kills amphibians within days.
- Fish, insects, and other aquatic life that naturally feed on aquatic weeds are also harmed by Roundup.
- Killing off animal life in a pond with Roundup creates the perfect conditions for pond weeds to take over.
Spraying Roundup on aquatic weeds creates a circular problem. The Roundup will kill the aquatic plants for a short time, but will also wipe out the animals in treated bodies of water. This disrupts the ecosystem by removing insects and fish that eat aquatic plants. Your pond weeds will emerge stronger than ever by next season without any animals that feed on them.
What Ingredients in Roundup Make it Dangerous for Ponds?
Surprisingly, it isn’t the active ingredient in Roundup that makes it unsafe for use on emergent weeds in ponds. It’s actually the surfactant in Roundup that is dangerous to aquatic animals. This additive is designed to help Roundup stick to weeds, but it is extremely dangerous for many animal species.
- The surfactant in Roundup is deadly to aquatic animals.
- Glyphosate, which is the weed killer in Roundup, is considered safe for use in aquatic herbicides.
- Kill aquatic weeds with a water-safe glyphosate product to prevent killing wildlife in and around ponds.
It is considered safe to use glyphosate products to kill aquatic weeds. However, any glyphosate-based aquatic herbicides must be mixed with a water-safe surfactant. This will give your herbicide the same killing power as Roundup without the danger of killing fish and other wildlife.
What is the Best Herbicide for Ponds?
Rodeo herbicide is the top choice for killing weeds in ponds. Rodeo is made with glyphosate, the same active ingredient in Roundup. When you compare Rodeo vs. Roundup, Rodeo emerges as the clear favorite for killing weeds in the water. After all, Rodeo has the same weed-killing power as Roundup, just without the downsides.
- Use this Rodeo herbicide to kill weeds in ponds.
- Mix Rodeo with this water-safe surfactant to kill all types of weeds in ponds.
When using Rodeo, make sure to mix it with a surfactant engineered for use in bodies of water. These surfactants will not harm fish and amphibians, unlike the ingredients in standard Roundup.
Can You Use Roundup on Pond Weeds
Do not use Roundup spray on any types of weeds growing in or around the edges of ponds. It’s important to keep these facts in mind:
- Roundup is not approved for aquatic weed management.
- If you spray Roundup on or near ponds it can kill mass quantities of amphibians and other wildlife.
- The surfactants in Roundup—not the weed killer—are the deadly ingredient.
- Spray a glyphosate herbicide, such as Rodeo, on your pond.
- When mixed with a water-safe surfactant, Rodeo herbicide has the same killing power as Roundup but won’t harm wildlife.
Whether you’re tackling alligator weed, filamentous algae, or invasive water lilies, a water-safe glyphosate herbicide like Rodeo will get the job done. As a bonus, you will not do damage to the fish, frogs, and other creatures living in your pond.