What is it? | Impacts | Where is it? | How can you help?
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What is European frog-bit?

European frog-bit (Hydrocharis morsus-ranae) is a free-floating aquatic invasive species that looks like a miniature water lily. Its leaves are smaller than native water lily leaves, reaching only the size of a quarter. When blooming, frog-bit has white three-petaled flowers with yellow centers.

How does European frog-bit impact you?

European frog-bit grows rapidly, forming thick mats. The thick mats that this species can form impede boat travel, prevent ducks from landing and block light from reaching plants below the surface. Additionally, the die off of thick mats can lead to low oxygen conditions in the water, affecting fish, turtles and frogs.

Learn more about frog-bit and it’s impacts in Michigan

Dense European frog-bit leaves with flowers blooming

Where is European frog-bit found?

European frog-bit is found in 16 small retention ponds and wetland complexes in Novi and Northville. Oakland County CISMA is leading a grant with watershed council partners to expand surveys for European frog-bit throughout southwestern Oakland County.

Wondering how European frog-bit came to southeast Michigan? Frog-bit was initially planted in an arboretum in Ontario, Canada and escaped into the Great Lakes several years later. Frog-bit is now relatively common in the Great Lakes, especially in Lake Huron, but remains rare inland. We don’t know for sure how frog-bit was transported to southeast Michigan. It may have been transported on gear from Lake Huron or escaped from someone’s backyard water garden.

The discovery of European frog-bit in southeast Michigan is a good reminder not release plants or pets into the environment! Plants like these take away resources from native plants and can negatively impact recreation. Follow the advice of campaigns like RIPPLE, Clean Drain Dry, and Play Clean Go to keep our ecosystems intact.

2021 Survey & Treatment stats:

How can I help?

  • If you think you may have this species in your pond, please take a photo and contact us! Small infestations can be hand-pulled and left to dry on land, whereas large populations require a more intensive treatment method.
  • If you live in southwestern Oakland County, please allow project partners to survey your property for European frog-bit. During the survey, people will walk around any water bodies and perform a quick test for submerged watch list species; as shown in this video.
  • Interested in having your pond surveyed, even if you don’t live in southwestern Oakland County? Contact Us!
  • Clean Drain Dry your boat to ensure any aquatic invaders you encounter stay put!
  • Learn more from our Homeowner’s guide to European frog-bit control


Events and Presentations

Project Partners

Oakland County CISMA is partnering with the Clinton River Watershed Council, Friends of the Rouge and the Huron River Watershed Council. These partners will be doing the bulk of the landowner contact and survey work.

Funding Acknowledgement

The European frog-bit survey project is funded by the Michigan Invasive Species Grant Program (www.michigan.gov/invasives) .

Potential European frog-bit survey locations in southwestern Oakland County.

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