Season shown in 6 of Ohio's 88 counties. Explore Ohio
No result yet (2)
Recorded, too few records for a result (50)
Recorded, season not shown (30)
Season shown (6)
Boundaries: U.S. Census Bureau, 2025 Cartographic Boundary Files, 1:500,000. Show as a table
Counties as a table
common milkweed by Ohio county: records and mapped range
County
Records
Adams County
33 · Recorded, season not shown
Allen County
42 · Recorded, season not shown
Ashland County
22 · Recorded, season not shown
Ashtabula County
27 · Recorded, season not shown
Athens County
75 · Season shown
Auglaize County
Recorded, too few records for a result
Belmont County
Recorded, too few records for a result
Brown County
Recorded, too few records for a result
Butler County
86 · Recorded, season not shown
Carroll County
Recorded, too few records for a result
Champaign County
Recorded, too few records for a result
Clark County
32 · Recorded, season not shown
Clermont County
82 · Recorded, season not shown
Clinton County
Recorded, too few records for a result
Columbiana County
Recorded, too few records for a result
Coshocton County
Recorded, too few records for a result
Crawford County
Recorded, too few records for a result
Cuyahoga County
438 · Recorded, season not shown
Darke County
Recorded, too few records for a result
Defiance County
Recorded, too few records for a result
Delaware County
99 · Recorded, season not shown
Erie County
49 · Recorded, season not shown
Fairfield County
42 · Recorded, season not shown
Fayette County
No qualifying records yet
Franklin County
414 · Season shown
Fulton County
Recorded, too few records for a result
Gallia County
Recorded, too few records for a result
Geauga County
55 · Recorded, season not shown
Greene County
67 · Recorded, season not shown
Guernsey County
Recorded, too few records for a result
Hamilton County
312 · Recorded, season not shown
Hancock County
25 · Recorded, season not shown
Hardin County
Recorded, too few records for a result
Harrison County
Recorded, too few records for a result
Henry County
Recorded, too few records for a result
Highland County
Recorded, too few records for a result
Hocking County
42 · Recorded, season not shown
Holmes County
Recorded, too few records for a result
Huron County
Recorded, too few records for a result
Jackson County
Recorded, too few records for a result
Jefferson County
Recorded, too few records for a result
Knox County
Recorded, too few records for a result
Lake County
87 · Season shown
Lawrence County
Recorded, too few records for a result
Licking County
71 · Recorded, season not shown
Logan County
Recorded, too few records for a result
Lorain County
100 · Recorded, season not shown
Lucas County
402 · Recorded, season not shown
Madison County
22 · Recorded, season not shown
Mahoning County
27 · Recorded, season not shown
Marion County
Recorded, too few records for a result
Medina County
51 · Recorded, season not shown
Meigs County
Recorded, too few records for a result
Mercer County
Recorded, too few records for a result
Miami County
24 · Recorded, season not shown
Monroe County
Recorded, too few records for a result
Montgomery County
77 · Season shown
Morgan County
Recorded, too few records for a result
Morrow County
Recorded, too few records for a result
Muskingum County
Recorded, too few records for a result
Noble County
Recorded, too few records for a result
Ottawa County
30 · Season shown
Paulding County
No qualifying records yet
Perry County
Recorded, too few records for a result
Pickaway County
Recorded, too few records for a result
Pike County
Recorded, too few records for a result
Portage County
73 · Recorded, season not shown
Preble County
Recorded, too few records for a result
Putnam County
Recorded, too few records for a result
Richland County
27 · Recorded, season not shown
Ross County
Recorded, too few records for a result
Sandusky County
Recorded, too few records for a result
Scioto County
Recorded, too few records for a result
Seneca County
Recorded, too few records for a result
Shelby County
Recorded, too few records for a result
Stark County
64 · Recorded, season not shown
Summit County
304 · Season shown
Trumbull County
23 · Recorded, season not shown
Tuscarawas County
Recorded, too few records for a result
Union County
Recorded, too few records for a result
Van Wert County
Recorded, too few records for a result
Vinton County
Recorded, too few records for a result
Warren County
61 · Recorded, season not shown
Washington County
Recorded, too few records for a result
Wayne County
54 · Recorded, season not shown
Williams County
Recorded, too few records for a result
Wood County
120 · Recorded, season not shown
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 Warren County
Late May to early July, middle week late June
Recorded in two separate seasons, each shown with its own early, middle and late weeks. A later season is not shown: the weeks are still too uncertain.
JanFebMarAprMayJunJulAugSepOctNovDec
Show over the bars
Recording in Warren County · records of all species each week, 16,872 in all
Records per week from 61 records in 8 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 common milkweed in Warren County each week, and records of all species
Week
Records of common milkweed
Years recorded
Records of all species
Jan 4–10
1
1
108
Jan 11–17
0
0
29
Jan 18–24
0
0
28
Jan 25–31
0
0
37
Feb 1–7
0
0
23
Feb 8–14
0
0
38
Feb 15–21
0
0
66
Feb 22–28
0
0
65
Mar 1–7
0
0
53
Mar 8–14
0
0
70
Mar 15–21
0
0
116
Mar 22–28
0
0
117
Mar 29 – Apr 4
0
0
396
Apr 5–11
0
0
254
Apr 12–18
0
0
324
Apr 19–25
0
0
336
Apr 26 – May 2
0
0
539
May 3–9
0
0
323
May 10–16
0
0
423
May 17–23
1
1
420
May 24–30
0
0
378
May 31 – Jun 6
7
6
696
Jun 7–13
1
1
759
Jun 14–20
6
5
727
Jun 21–27
10
6
558
Jun 28 – Jul 4
6
4
552
Jul 5–11
2
2
695
Jul 12–18
1
1
643
Jul 19–25
0
0
564
Jul 26 – Aug 1
5
3
530
Aug 2–8
4
3
491
Aug 9–15
3
2
720
Aug 16–22
1
1
565
Aug 23–29
2
2
534
Aug 30 – Sep 5
4
3
719
Sep 6–12
3
3
619
Sep 13–19
4
2
584
Sep 20–26
0
0
390
Sep 27 – Oct 3
0
0
403
Oct 4–10
0
0
264
Oct 11–17
0
0
277
Oct 18–24
0
0
266
Oct 25–31
0
0
204
Nov 1–7
0
0
159
Nov 8–14
0
0
141
Nov 15–21
0
0
78
Nov 22–28
0
0
220
Nov 29 – Dec 5
0
0
53
Dec 6–12
0
0
58
Dec 13–19
0
0
45
Dec 20–26
0
0
75
Dec 27 – Jan 2
0
0
140
Reported in flower
Only 1 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 5 records here show fruit, too few to show a fruiting season. One needs at least 20 records from 5 different years.
In Ohio
Late May to early November, middle week Jul 26 – Aug 1
Middle week · Jul 26 – Aug 1
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 4,998 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 1,417 dates. Latest record: December 2025.
Show as a table
Records of common milkweed in Ohio each week, and records of all species
Week
Records of common milkweed
Years recorded
Records of all species
Jan 4–10
9
5
6,211
Jan 11–17
7
5
5,146
Jan 18–24
11
5
4,645
Jan 25–31
10
5
4,698
Feb 1–7
11
5
6,023
Feb 8–14
9
2
5,888
Feb 15–21
6
2
5,436
Feb 22–28
10
5
6,846
Mar 1–7
6
5
8,321
Mar 8–14
4
3
10,384
Mar 15–21
7
5
12,620
Mar 22–28
2
2
13,949
Mar 29 – Apr 4
11
7
19,661
Apr 5–11
5
4
26,860
Apr 12–18
5
3
39,925
Apr 19–25
7
4
41,623
Apr 26 – May 2
21
8
56,391
May 3–9
27
8
52,952
May 10–16
30
6
53,785
May 17–23
62
8
57,698
May 24–30
76
10
54,651
May 31 – Jun 6
145
10
53,099
Jun 7–13
167
10
53,700
Jun 14–20
297
10
56,625
Jun 21–27
352
10
55,361
Jun 28 – Jul 4
433
10
58,477
Jul 5–11
379
10
61,336
Jul 12–18
255
10
64,722
Jul 19–25
200
10
69,753
Jul 26 – Aug 1
142
9
59,416
Aug 2–8
187
10
59,712
Aug 9–15
156
9
55,994
Aug 16–22
169
9
54,328
Aug 23–29
134
10
51,772
Aug 30 – Sep 5
139
9
57,167
Sep 6–12
186
10
59,075
Sep 13–19
181
9
54,543
Sep 20–26
185
9
45,860
Sep 27 – Oct 3
227
10
43,180
Oct 4–10
322
9
37,841
Oct 11–17
129
9
30,824
Oct 18–24
70
9
21,156
Oct 25–31
38
8
19,021
Nov 1–7
42
8
14,172
Nov 8–14
37
7
12,621
Nov 15–21
21
6
7,965
Nov 22–28
26
7
8,136
Nov 29 – Dec 5
11
4
6,083
Dec 6–12
10
6
6,004
Dec 13–19
6
3
5,423
Dec 20–26
8
5
5,661
Dec 27 – Jan 2
8
5
8,459
Reported in flower
Usually reported in flower mid-June to early August, middle week Jun 28 – Jul 4.
From 164 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
Usually reported in fruit mid-July to mid-November, middle week Sep 27 – Oct 3.
From 275 records that show fruit. Not every photo of a plant in fruit is marked as fruiting, so this shows when people reported it in fruit, not when it fruits.
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.
hemp dogbaneApocynum cannabinumOften confused in Ohio: 94 identifications in Ohio named one where the other was meant
prairie milkweedAsclepias sullivantiiOften confused in Ohio: 41 identifications in Ohio named one where the other was meant
purple milkweedAsclepias purpurascensOften confused in Ohio: 23 identifications in Ohio named one where the other was meant
swamp milkweedAsclepias incarnataOften confused in Ohio: 16 identifications in Ohio named one where the other was meant
poke milkweedAsclepias exaltata120 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.
Land cover where it is recorded
Land cover
Its recordsAll Ohio records
Developed
63%49%
Farmland
23%11%
Forest
9%31%
Wetland
2%5%
Barren
1%0.6%
Grassland and shrub
1%0.9%
Open water
0.9%3%
From 3,267 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.
