Creeping water primrose - Ask Extension
What can you use to eliminate creeping water primrose in backyard pond? It is everywhere around the pond (probably from herons bringing it in). We ha...
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Creeping water primrose #892789
Asked February 18, 2025, 3:27 PM EST
What can you use to eliminate creeping water primrose in backyard pond? It is everywhere around the pond (probably from herons bringing it in). We have tried to pull it out by hand but this is very labor intensive and hard to keep up with. I see there are different chemicals on the market. We don’t want to kill the fish that happen to be in there. Is there something we can use that is effective but safe to other wildlife/dogs/nearby plants?
Kent County Delaware
Expert Response
Hello!
Creeping water primrose is very persistent as you may have found. An integrated approach is the best way to combat this weed. Physical removal is the best tool to get started, especially if there is already a lot of biomass present. This is usually easier when the majority of the biomass is floating with only the shallow portions rooted into substrate. Caution must be taken because fragments left in the pond have the potential to reroot. An aquatic approved herbicide is also a valuable tool and there are plenty of options. 2 active ingredients that work well are glyphosate and triclopyr. While I can’t recommend trade names, the label will let you know if the product you select is aquatic approved or not. The label will also determine if an aquatic approved surfactant is necessary (this helps the herbicide stick to and penetrate the foliage). Foliar sprays in the late summer/early fall get the best root kill. This will be a multi-year effort to control but is possible to achieve. I recommend scouting regularly for new populations each year and tackling them when they are low in number. I’d be happy to review any product labels you select and can help determine if there are any off target risks or risks to wildlife/pets. If your pond has an outlet, it is necessary to ensure there is no outflow during and after treatment (length of time is dictated by herbicide label). If there is a significant portion of your pond covered by primrose or other aquatic vegetation/algae, partial treatments would be necessary to avoid hazardous drops in dissolved oxygen, which gets used up during decomposition of plant material. My email is <personal data hidden>, please feel free to reach out with questions or to set up a site visit. Thank you!!
Creeping water primrose is very persistent as you may have found. An integrated approach is the best way to combat this weed. Physical removal is the best tool to get started, especially if there is already a lot of biomass present. This is usually easier when the majority of the biomass is floating with only the shallow portions rooted into substrate. Caution must be taken because fragments left in the pond have the potential to reroot. An aquatic approved herbicide is also a valuable tool and there are plenty of options. 2 active ingredients that work well are glyphosate and triclopyr. While I can’t recommend trade names, the label will let you know if the product you select is aquatic approved or not. The label will also determine if an aquatic approved surfactant is necessary (this helps the herbicide stick to and penetrate the foliage). Foliar sprays in the late summer/early fall get the best root kill. This will be a multi-year effort to control but is possible to achieve. I recommend scouting regularly for new populations each year and tackling them when they are low in number. I’d be happy to review any product labels you select and can help determine if there are any off target risks or risks to wildlife/pets. If your pond has an outlet, it is necessary to ensure there is no outflow during and after treatment (length of time is dictated by herbicide label). If there is a significant portion of your pond covered by primrose or other aquatic vegetation/algae, partial treatments would be necessary to avoid hazardous drops in dissolved oxygen, which gets used up during decomposition of plant material. My email is <personal data hidden>, please feel free to reach out with questions or to set up a site visit. Thank you!!
