Introduced and assessed as invasive in the lower 48 states
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.
Season shown in 1 of Ohio's 88 counties. Explore Ohio
No result yet (59)
Recorded, too few records for a result (26)
Recorded, season not shown (2)
Season shown (1)
Boundaries: U.S. Census Bureau, 2025 Cartographic Boundary Files, 1:500,000. Show as a table
Counties as a table
musk thistle by Ohio county: records and mapped range
County
Records
Adams County
Recorded, too few records for a result
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
Recorded, too few records for a result
Carroll County
No qualifying records yet
Champaign County
No qualifying records yet
Clark County
Recorded, too few records for a result
Clermont County
Recorded, too few records for a result
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
22 · Season shown
Darke County
No qualifying records yet
Defiance County
Recorded, too few records for a result
Delaware County
No qualifying records yet
Erie County
Recorded, too few records for a result
Fairfield County
Recorded, too few records for a result
Fayette County
Recorded, too few records for a result
Franklin County
Recorded, too few records for a result
Fulton County
No qualifying records yet
Gallia County
No qualifying records yet
Geauga County
No qualifying records yet
Greene County
40 · Recorded, season not shown
Guernsey County
No qualifying records yet
Hamilton County
55 · Recorded, season not shown
Hancock County
Recorded, too few records for a result
Hardin County
No qualifying records yet
Harrison County
Recorded, too few records for a result
Henry County
No qualifying records yet
Highland County
No qualifying records yet
Hocking County
No qualifying records yet
Holmes County
Recorded, too few records for a result
Huron County
Recorded, too few records for a result
Jackson County
No qualifying records yet
Jefferson County
Recorded, too few records for a result
Knox County
No qualifying records yet
Lake County
No qualifying records yet
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
Recorded, too few records for a result
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
Recorded, too few records for a result
Monroe County
No qualifying records yet
Montgomery County
Recorded, too few records for a result
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
Recorded, too few records for a result
Sandusky County
No qualifying records yet
Scioto County
No qualifying records yet
Seneca County
Recorded, too few records for a result
Shelby County
No qualifying records yet
Stark County
Recorded, too few records for a result
Summit County
Recorded, too few records for a result
Trumbull County
No qualifying records yet
Tuscarawas County
No qualifying records yet
Union County
Recorded, too few records for a result
Van Wert County
No qualifying records yet
Vinton County
No qualifying records yet
Warren County
Recorded, too few records for a result
Washington County
No qualifying records yet
Wayne County
No qualifying records yet
Williams County
No qualifying records yet
Wood County
No qualifying records yet
Wyandot County
Recorded, too few records for a result
No mapped range from the range source used, the USGS Gap Analysis Project, which maps land vertebrates only.
Season
When it is recorded
In Greene County
Not enough evidence
The weeks are still too uncertain to show a season. Based on 40 records in 6 of the 10 years from 2016 to 2025, above the minimum of 20 records from 5 different years.
JanFebMarAprMayJunJulAugSepOctNovDec
Show over the bars
Recording in Greene County · records of all species each week, 31,407 in all
Records per week from 40 records in 6 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
Records of musk thistle in Greene County each week, and records of all species
Week
Records of musk thistle
Years recorded
Records of all species
Jan 4–10
0
0
97
Jan 11–17
0
0
49
Jan 18–24
0
0
37
Jan 25–31
0
0
55
Feb 1–7
0
0
82
Feb 8–14
0
0
90
Feb 15–21
0
0
186
Feb 22–28
0
0
151
Mar 1–7
0
0
124
Mar 8–14
0
0
238
Mar 15–21
0
0
299
Mar 22–28
0
0
338
Mar 29 – Apr 4
1
1
561
Apr 5–11
0
0
537
Apr 12–18
2
1
738
Apr 19–25
0
0
793
Apr 26 – May 2
0
0
1,090
May 3–9
0
0
778
May 10–16
0
0
721
May 17–23
0
0
889
May 24–30
1
1
932
May 31 – Jun 6
0
0
889
Jun 7–13
5
5
1,186
Jun 14–20
5
2
1,205
Jun 21–27
6
4
1,059
Jun 28 – Jul 4
4
3
1,150
Jul 5–11
3
3
1,279
Jul 12–18
2
2
1,164
Jul 19–25
4
2
1,228
Jul 26 – Aug 1
2
1
1,533
Aug 2–8
1
1
1,324
Aug 9–15
2
2
1,105
Aug 16–22
0
0
957
Aug 23–29
0
0
942
Aug 30 – Sep 5
0
0
932
Sep 6–12
0
0
992
Sep 13–19
0
0
1,194
Sep 20–26
0
0
870
Sep 27 – Oct 3
0
0
677
Oct 4–10
2
1
614
Oct 11–17
0
0
533
Oct 18–24
0
0
305
Oct 25–31
0
0
307
Nov 1–7
0
0
214
Nov 8–14
0
0
227
Nov 15–21
0
0
155
Nov 22–28
0
0
110
Nov 29 – Dec 5
0
0
86
Dec 6–12
0
0
36
Dec 13–19
0
0
46
Dec 20–26
0
0
117
Dec 27 – Jan 2
0
0
186
Reported in flower
Only 5 records here show flowers, too few to show a flowering season. One needs at least 20 records from 5 different years.
Reported in fruit
Only 1 records here show fruit, too few to show a fruiting season. One needs at least 20 records from 5 different years.
In Ohio
Early May to early August, middle week Jun 14–20
Middle week · Jun 14–20
This week · Nov 8–14
JanFebMarAprMayJunJulAugSepOctNovDec
Show over the bars
Recording in Ohio · records of all species each week, 1,691,199 in all
Records per week from 325 records in 10 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 214 dates. Latest record: October 2025.
Show as a table
Records of musk thistle in Ohio each week, and records of all species
Week
Records of musk thistle
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
1
1
6,846
Mar 1–7
1
1
8,321
Mar 8–14
2
1
10,384
Mar 15–21
0
0
12,620
Mar 22–28
1
1
13,949
Mar 29 – Apr 4
2
2
19,661
Apr 5–11
0
0
26,860
Apr 12–18
2
1
39,925
Apr 19–25
1
1
41,623
Apr 26 – May 2
4
1
56,391
May 3–9
1
1
52,952
May 10–16
8
4
53,785
May 17–23
4
3
57,698
May 24–30
27
5
54,651
May 31 – Jun 6
28
9
53,099
Jun 7–13
54
8
53,700
Jun 14–20
53
8
56,625
Jun 21–27
41
8
55,361
Jun 28 – Jul 4
35
9
58,477
Jul 5–11
21
7
61,336
Jul 12–18
9
5
64,722
Jul 19–25
8
5
69,753
Jul 26 – Aug 1
5
3
59,416
Aug 2–8
3
3
59,712
Aug 9–15
4
3
55,994
Aug 16–22
1
1
54,328
Aug 23–29
1
1
51,772
Aug 30 – Sep 5
0
0
57,167
Sep 6–12
0
0
59,075
Sep 13–19
0
0
54,543
Sep 20–26
1
1
45,860
Sep 27 – Oct 3
0
0
43,180
Oct 4–10
3
2
37,841
Oct 11–17
0
0
30,824
Oct 18–24
2
2
21,156
Oct 25–31
0
0
19,021
Nov 1–7
0
0
14,172
Nov 8–14
1
1
12,621
Nov 15–21
1
1
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
Usually reported in flower late May to late July, middle week Jun 14–20.
From 27 records that show flowers. Not every photo of a plant in flower is marked as flowering, so this shows when people reported it in flower, not when it flowers.
Reported in fruit
Only 3 records here show fruit, too few to show a fruiting season. 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
Telling it apart
From what Ohio’s records show. Only what the records support is shown.
Bull ThistleCirsium vulgare432 identifications worldwide named one where the other was meant
creeping thistleCirsium arvense215 identifications worldwide named one where the other was meant
field thistleCirsium discolor27 identifications worldwide named one where the other was meant
prickly sowthistleSonchus asper22 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: recorded
Mar: recorded
Apr: recorded
May: recorded
Jun: recorded
Jul: recorded
Aug: recorded
Sep: recorded
Oct: recorded
Nov: recorded
Dec: no record
Not reported in Ohio in December to January, 2016 to 2025.
Land cover where it is recorded
Land cover
Its recordsAll Ohio records
Developed
48%49%
Farmland
34%11%
Forest
6%31%
Wetland
5%5%
Barren
4%0.6%
Open water
3%3%
Grassland and shrub
2%0.9%
From 198 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
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.
