European Frog-bit
Hydrocharis morsus-ranae L.
European Frog-bit in all of Ohio
- Kingdom
- Plantae
- Phylum
- Tracheophyta
- Class
- Liliopsida
- Order
- Alismatales
- Family
- Hydrocharitaceae
- Genus
- Hydrocharis
Introduced and invasive status
Invasive in Ohio: Ohio Department of Agriculture (opens in a new tab)
Also listed
- Introduced in Ohio: iNaturalist (opens in a new tab)
- Introduced and assessed as invasive in the lower 48 states
Ohio law lists it as an invasive plant: not native to Ohio, and causing, or likely to cause, economic, environmental or human health harm.
iNaturalist's volunteer curators list it as introduced in their Ohio checklist.
US-RIIS assesses a species as invasive when it causes, or is likely to cause, harm there, or is at least locally abundant and harmful ecologically, economically, or to health.
Status: Simpson A, Sellers E, Pagad S (2023). United States Register of Introduced and Invasive Species (US-RIIS), ver. 2.0. U.S. Geological Survey, https://doi.org/10.5066/P9KFFTOD (opens in a new tab)
Range
Where it is recorded
Season shown in 1 of Ohio's 88 counties. Explore Ohio
- No result yet (81)
- Recorded, too few records for a result (5)
- Recorded, season not shown (1)
- Season shown (1)
Counties as a table
| County | Records |
|---|---|
| Adams County | No qualifying records yet |
| Allen County | No qualifying records yet |
| Ashland County | No qualifying records yet |
| Ashtabula County | No qualifying records yet |
| Athens County | No qualifying records yet |
| Auglaize County | No qualifying records yet |
| Belmont County | No qualifying records yet |
| Brown County | No qualifying records yet |
| Butler County | No qualifying records yet |
| Carroll County | No qualifying records yet |
| Champaign County | No qualifying records yet |
| Clark County | No qualifying records yet |
| Clermont County | No qualifying records yet |
| Clinton County | No qualifying records yet |
| Columbiana County | No qualifying records yet |
| Coshocton County | No qualifying records yet |
| Crawford County | No qualifying records yet |
| Cuyahoga County | Recorded, too few records for a result |
| Darke County | No qualifying records yet |
| Defiance County | No qualifying records yet |
| Delaware County | No qualifying records yet |
| Erie County | 30 · Season shown |
| Fairfield County | No qualifying records yet |
| Fayette County | No qualifying records yet |
| Franklin County | No qualifying records yet |
| Fulton County | No qualifying records yet |
| Gallia County | No qualifying records yet |
| Geauga County | No qualifying records yet |
| Greene County | No qualifying records yet |
| Guernsey County | No qualifying records yet |
| Hamilton County | No qualifying records yet |
| Hancock County | No qualifying records yet |
| Hardin County | No qualifying records yet |
| Harrison County | No qualifying records yet |
| Henry County | No qualifying records yet |
| Highland County | No qualifying records yet |
| Hocking County | No qualifying records yet |
| Holmes County | No qualifying records yet |
| Huron County | No qualifying records yet |
| Jackson County | No qualifying records yet |
| Jefferson County | No qualifying records yet |
| Knox County | No qualifying records yet |
| Lake County | Recorded, too few records for a result |
| Lawrence County | No qualifying records yet |
| Licking County | No qualifying records yet |
| Logan County | No qualifying records yet |
| Lorain County | Recorded, too few records for a result |
| Lucas County | 26 · Recorded, season not shown |
| Madison County | No qualifying records yet |
| Mahoning County | No qualifying records yet |
| Marion County | No qualifying records yet |
| Medina County | No qualifying records yet |
| Meigs County | No qualifying records yet |
| Mercer County | No qualifying records yet |
| Miami County | No qualifying records yet |
| Monroe County | No qualifying records yet |
| Montgomery County | No qualifying records yet |
| Morgan County | No qualifying records yet |
| Morrow County | No qualifying records yet |
| Muskingum County | No qualifying records yet |
| Noble County | No qualifying records yet |
| Ottawa County | Recorded, too few records for a result |
| Paulding County | No qualifying records yet |
| Perry County | No qualifying records yet |
| Pickaway County | No qualifying records yet |
| Pike County | No qualifying records yet |
| Portage County | No qualifying records yet |
| Preble County | No qualifying records yet |
| Putnam County | No qualifying records yet |
| Richland County | No qualifying records yet |
| Ross County | No qualifying records yet |
| Sandusky County | No qualifying records yet |
| Scioto County | No qualifying records yet |
| Seneca County | No qualifying records yet |
| Shelby County | No qualifying records yet |
| Stark County | No qualifying records yet |
| Summit County | No qualifying records yet |
| Trumbull County | No qualifying records yet |
| Tuscarawas County | No qualifying records yet |
| Union County | No qualifying records yet |
| Van Wert County | No qualifying records yet |
| Vinton County | No qualifying records yet |
| Warren County | No qualifying records yet |
| Washington County | No qualifying records yet |
| Wayne County | Recorded, too few records for a result |
| Williams County | No qualifying records yet |
| Wood County | No qualifying records yet |
| Wyandot County | No qualifying records yet |
No mapped range from the range source used, the USGS Gap Analysis Project, which maps land vertebrates only.
Season
When it is recorded
In Lucas County
Not enough evidence
Records per week from 26 records in 7 of the 10 years from 2016 to 2025. Shows when people recorded it, not a season or how common it is.
Show as a table
| Week | Records of European Frog-bit | Years recorded | Records of all species |
|---|---|---|---|
| Jan 4–10 | 0 | 0 | 168 |
| Jan 11–17 | 0 | 0 | 125 |
| Jan 18–24 | 0 | 0 | 85 |
| Jan 25–31 | 0 | 0 | 64 |
| Feb 1–7 | 0 | 0 | 81 |
| Feb 8–14 | 0 | 0 | 84 |
| Feb 15–21 | 0 | 0 | 100 |
| Feb 22–28 | 0 | 0 | 101 |
| Mar 1–7 | 0 | 0 | 137 |
| Mar 8–14 | 0 | 0 | 150 |
| Mar 15–21 | 0 | 0 | 202 |
| Mar 22–28 | 0 | 0 | 278 |
| Mar 29 – Apr 4 | 0 | 0 | 355 |
| Apr 5–11 | 0 | 0 | 421 |
| Apr 12–18 | 0 | 0 | 788 |
| Apr 19–25 | 0 | 0 | 700 |
| Apr 26 – May 2 | 0 | 0 | 1,295 |
| May 3–9 | 0 | 0 | 2,514 |
| May 10–16 | 0 | 0 | 5,269 |
| May 17–23 | 3 | 2 | 4,884 |
| May 24–30 | 0 | 0 | 1,850 |
| May 31 – Jun 6 | 1 | 1 | 1,817 |
| Jun 7–13 | 0 | 0 | 1,677 |
| Jun 14–20 | 1 | 1 | 1,553 |
| Jun 21–27 | 1 | 1 | 1,586 |
| Jun 28 – Jul 4 | 4 | 2 | 1,749 |
| Jul 5–11 | 1 | 1 | 1,976 |
| Jul 12–18 | 5 | 4 | 2,118 |
| Jul 19–25 | 2 | 2 | 2,090 |
| Jul 26 – Aug 1 | 0 | 0 | 1,646 |
| Aug 2–8 | 0 | 0 | 1,938 |
| Aug 9–15 | 1 | 1 | 1,606 |
| Aug 16–22 | 2 | 1 | 1,660 |
| Aug 23–29 | 0 | 0 | 1,644 |
| Aug 30 – Sep 5 | 0 | 0 | 1,585 |
| Sep 6–12 | 0 | 0 | 1,913 |
| Sep 13–19 | 3 | 2 | 1,724 |
| Sep 20–26 | 0 | 0 | 2,839 |
| Sep 27 – Oct 3 | 0 | 0 | 2,478 |
| Oct 4–10 | 0 | 0 | 2,869 |
| Oct 11–17 | 2 | 1 | 1,470 |
| Oct 18–24 | 0 | 0 | 598 |
| Oct 25–31 | 0 | 0 | 496 |
| Nov 1–7 | 0 | 0 | 365 |
| Nov 8–14 | 0 | 0 | 264 |
| Nov 15–21 | 0 | 0 | 168 |
| Nov 22–28 | 0 | 0 | 160 |
| Nov 29 – Dec 5 | 0 | 0 | 127 |
| Dec 6–12 | 0 | 0 | 133 |
| Dec 13–19 | 0 | 0 | 113 |
| Dec 20–26 | 0 | 0 | 152 |
| Dec 27 – Jan 2 | 0 | 0 | 170 |
Reported in flower
Only 3 records here show flowers, too few to show a flowering season. One needs at least 20 records from 5 different years.
Reported in fruit
No records here show fruit yet, so there is no fruiting season to show. One needs at least 20 records from 5 different years.
In Ohio
Mid-May to early October, middle week Jul 19–25
Records per week from 134 records in 9 of the 10 years from 2016 to 2025. Shows when people recorded it, not how common it is. The grey bars show how many records of all species were made here each week, so you can see when recording itself was high or low; the season is not adjusted by them.
Recorded on 91 dates. Latest record: September 2025.
Show as a table
| Week | Records of European Frog-bit | Years recorded | Records of all species |
|---|---|---|---|
| Jan 4–10 | 0 | 0 | 6,211 |
| Jan 11–17 | 0 | 0 | 5,146 |
| Jan 18–24 | 0 | 0 | 4,645 |
| Jan 25–31 | 0 | 0 | 4,698 |
| Feb 1–7 | 0 | 0 | 6,023 |
| Feb 8–14 | 0 | 0 | 5,888 |
| Feb 15–21 | 0 | 0 | 5,436 |
| Feb 22–28 | 0 | 0 | 6,846 |
| Mar 1–7 | 0 | 0 | 8,321 |
| Mar 8–14 | 0 | 0 | 10,384 |
| Mar 15–21 | 0 | 0 | 12,620 |
| Mar 22–28 | 1 | 1 | 13,949 |
| Mar 29 – Apr 4 | 0 | 0 | 19,661 |
| Apr 5–11 | 0 | 0 | 26,860 |
| Apr 12–18 | 0 | 0 | 39,925 |
| Apr 19–25 | 0 | 0 | 41,623 |
| Apr 26 – May 2 | 0 | 0 | 56,391 |
| May 3–9 | 1 | 1 | 52,952 |
| May 10–16 | 2 | 2 | 53,785 |
| May 17–23 | 5 | 3 | 57,698 |
| May 24–30 | 0 | 0 | 54,651 |
| May 31 – Jun 6 | 3 | 1 | 53,099 |
| Jun 7–13 | 0 | 0 | 53,700 |
| Jun 14–20 | 4 | 3 | 56,625 |
| Jun 21–27 | 3 | 3 | 55,361 |
| Jun 28 – Jul 4 | 9 | 4 | 58,477 |
| Jul 5–11 | 17 | 7 | 61,336 |
| Jul 12–18 | 11 | 6 | 64,722 |
| Jul 19–25 | 16 | 8 | 69,753 |
| Jul 26 – Aug 1 | 13 | 6 | 59,416 |
| Aug 2–8 | 5 | 2 | 59,712 |
| Aug 9–15 | 9 | 5 | 55,994 |
| Aug 16–22 | 8 | 3 | 54,328 |
| Aug 23–29 | 1 | 1 | 51,772 |
| Aug 30 – Sep 5 | 2 | 2 | 57,167 |
| Sep 6–12 | 7 | 2 | 59,075 |
| Sep 13–19 | 8 | 4 | 54,543 |
| Sep 20–26 | 1 | 1 | 45,860 |
| Sep 27 – Oct 3 | 1 | 1 | 43,180 |
| Oct 4–10 | 0 | 0 | 37,841 |
| Oct 11–17 | 7 | 1 | 30,824 |
| Oct 18–24 | 0 | 0 | 21,156 |
| Oct 25–31 | 0 | 0 | 19,021 |
| Nov 1–7 | 0 | 0 | 14,172 |
| Nov 8–14 | 0 | 0 | 12,621 |
| Nov 15–21 | 0 | 0 | 7,965 |
| Nov 22–28 | 0 | 0 | 8,136 |
| Nov 29 – Dec 5 | 0 | 0 | 6,083 |
| Dec 6–12 | 0 | 0 | 6,004 |
| Dec 13–19 | 0 | 0 | 5,423 |
| Dec 20–26 | 0 | 0 | 5,661 |
| Dec 27 – Jan 2 | 0 | 0 | 8,459 |
Reported in flower
Only 9 records here show flowers, too few to show a flowering season. One needs at least 20 records from 5 different years.
Reported in fruit
No records here show fruit yet, so there is no fruiting season to show. One needs at least 20 records from 5 different years.
What these results show
These results show when people recorded a species, not when or where it occurs. Missing weeks and low counts do not mean absence or scarcity, and counts are not abundance. Contributed records reflect where, when and what people chose to observe.
Identification
How to identify it
Often confused with
- greater duckweed Spirodela polyrhiza30 identifications worldwide named one where the other was meant
- American white waterlily Nymphaea odorata13 identifications worldwide named one where the other was meant
- water fringe Nymphoides peltata11 identifications worldwide named one where the other was meant
From iNaturalist’s similar-species counts, refreshed monthly: confusions in Ohio first, then worldwide. Only species with an Ohio result are listed.
Months not reported
- Jan: no record
- Feb: no record
- Mar: recorded
- Apr: no record
- May: recorded
- Jun: recorded
- Jul: recorded
- Aug: recorded
- Sep: recorded
- Oct: recorded
- Nov: no record
- Dec: no record
Not reported in Ohio in April and November to February, 2016 to 2025.
Land cover where it is recorded
| Land cover | Its recordsAll Ohio records |
|---|---|
| Wetland | 67%5% |
| Developed | 30%49% |
| Open water | 3%3% |
| Forest | 1%31% |
From 78 records placed within 100 m, beside all Ohio records placed the same way. People record where they go, so this shows where records come from, not where the species lives. Land cover: USGS Annual NLCD, 2025 (opens in a new tab)
Sources
Where these results come from
- Records from iNaturalist research-grade observations and expert-identified GBIF datasets, CC0, CC BY and CC BY-NC. Sources
- Seasons use the published method and its evidence thresholds. Methods
- See it on iNaturalist (opens in a new tab)OpenPhenology is independent and not affiliated with iNaturalist.
Records behind the Ohio result
134 records from 2 datasets.
- iNaturalist Research-grade Observations (opens in a new tab) · iNaturalist.org · 117 recordsiNaturalist contributors, iNaturalist (2026). iNaturalist Research-grade Observations. iNaturalist.org. Occurrence dataset https://doi.org/10.15468/ab3s5x accessed via GBIF.org on 2026-11-13.
- Aggregated occurrence records of invasive European frog-bit (Hydrocharis morsus-ranae L.) across North America (opens in a new tab) · Biodiversity Data Journal · 17 recordsHansen S, Cahill B, Hackett R, Monfils M, Goebel R, Asencio S, Monfils A (2022). Aggregated occurrence records of invasive European frog-bit (Hydrocharis morsus-ranae L.) across North America. Biodiversity Data Journal. Occurrence dataset https://doi.org/10.15468/jsab2y accessed via GBIF.org on 2026-11-13.
To cite: the GBIF downloads doi:10.15468/dl.8m7c3d (opens in a new tab), doi:10.15468/dl.y2jkt8 (opens in a new tab).
A spreadsheet (CSV) with a link to each record, on iNaturalist or GBIF. Records whose location was hidden by the observer or the source are counted but not linked.