Poison Hemlock (Conium maculatum) is in the carrot family family (Apiaceae). Across the U.S., iNaturalist users have logged 5,794 research-grade flowering observations of it in our sample, peaking in May.
Nationally it blooms mainly from May to June, but timing varies a lot by state and elevation — see the table below.
When to photograph Poison Hemlock: observations by month (U.S.)
About Poison Hemlock
Conium maculatum, the hemlock or poison hemlock, is a highly poisonous biennial herbaceous flowering plant in the carrot family Apiaceae, native to Europe and North Africa. A hardy plant capable of living in a variety of environments, hemlock is widely naturalized in locations outside its native range.From Wikipedia via iNaturalist — article, CC BY-SA.
Poison Hemlock by state
| State | Observations | Peak month | Main season |
|---|---|---|---|
| California | 1,985 | May | Apr–Jun |
| Washington | 535 | June | Jun–Jun |
| Texas | 464 | April | Mar–May |
| Oregon | 400 | June | May–Jun |
| Virginia | 277 | May | May–Jun |
| Pennsylvania | 221 | June | May–Jun |
| Ohio | 208 | June | May–Jun |
| Kentucky | 194 | May | May–Jun |
| Missouri | 154 | May | May–May |
| Colorado | 130 | June | Jun–Jun |
| Tennessee | 130 | May | May–Jun |
| Illinois | 127 | May | May–Jun |
| Arkansas | 100 | May | May–May |
| Arizona | 86 | May | Apr–Jun |
| Indiana | 80 | May | May–Jun |
| Idaho | 57 | June | May–Jul |
| Kansas | 55 | May | May–Jun |
| Oklahoma | 55 | May | May–May |
| New Jersey | 53 | May | May–Jun |
| Maryland | 51 | May | May–Jun |
| North Carolina | 50 | May | May–Jun |
| Delaware | 48 | May | May–Jun |
| Iowa | 47 | June | May–Jun |
| Montana | 38 | July | Jun–Jul |
| New York | 37 | June | Jun–Jun |
| New Mexico | 32 | June | May–Jul |
| Utah | 29 | June | May–Jul |
| Alabama | 28 | May | May–May |
| Nebraska | 24 | June | May–Jun |
| West Virginia | 20 | June | May–Jun |
| Michigan | 19 | June | May–Jun |
| Wisconsin | 15 | June | Jun–Jul |
| Wyoming | 10 | July | Jun–Jul |
| Massachusetts | 8 | June | Jun–Jul |
| Minnesota | 7 | June | Jun–Jul |
| Nevada | 6 | May | May–Jun |
Main season = months with at least 30% of the state's peak-month count.
Related wildflowers (carrot family)
Wild Carrot
Harbinger of Spring
Common Cowparsnip
golden Alexanders
Purple Sanicle
Aniseroot
Wild Parsnip
Pacific Sanicle
Photography tips
- Photograph flowers on calm, overcast mornings to avoid wind blur and harsh shadows.
- Get low: a shallow depth of field (f/2.8–f/5.6) isolates a bloom against soft color.
- Stay on trails — trampling meadows kills plants and ruins next year's display.
- Try a kaleidoscope abstract of a single bloom with our online kaleidoscope tool.
FAQ
When is the best time to photograph Poison Hemlock?
Nationally, May has the most observations, with the main season from May to June.
Where is Poison Hemlock most often seen?
The most observations come from California, Washington, Texas.