It is easy mistake the poison hemlock plant (Conium maculatum) with another plant called “Queen Anne’s lace” (Daucus carota – and also called wild carrot).
Poison hemlock and Queen Anne’s lace belong to the same family of plants (carrots and parsley). So, not only are the delicate, pretty white flowers similar, the leaves are similar too!
Over the years, I’ve enjoyed seeing the beautiful white flowers of these plants in different parts of California. I spent a lot of time on the road in my prior work — and a lot of time stuck in traffic in the Bay Area — which means, a lot of time to look out the window and see plants growing on the side the road.
I thought these flowers all came from the same plant (Queen Anne’s lace) and did not know very much about them.
Through the Earth-Friendly Chroniclers’ Challenge this month — focused on biodiversity — I now know that there are two different plants with very similar flowers that grow here in my ecoregion.
Challenge, #10 asked that we play a naturalist version of I “Spy!” at our ecoregion, to take a camera, and observe what we see. I went to the greenbelt space behind where we live here in the Central Coast.
I “spied” these familiar flowers and wanted to know more, because there were many of the plants here. Most were already flowering, with white, lacy blooms. There were rather tall plants (taller than me) and some of the flowers came from shorter plants.
Unlike the yellow starthistle or iceplants (posted for Challenge #9), which are listed as a high priority invasive plant, the Calflora website listed the poison hemlock (Conium maculatum) as a “moderate” problem.
While it is good to know that this plant is not (at least not yet) as problematic as the iceplant or starthistle in California, it was disturbing to learn that these plants have naturalized here and are now invasive.
Even more disturbing is to learn that all parts of these plants are toxic (flowers, seeds, leaves, canes)…and even the dead parts of the plants can remain toxic for up to 3 years.
And not mildly toxic, or an irritant, but really TOXIC, as in the plant is deadly for humans and animals.
Poison hemlock is native to Europe’s Mediterranean region. The ancient Greeks used the plant to poison prisoners condemned to death — including the philosopher Socrates.
Because these plants are in the same family of plants as carrots and parsley, it is understandable how people can accidentally ingest the plants. From a May, 2015 Food Safety News article:
All parts of poison-hemlock can kill humans and animals, even when it is dried. Foragers can easily mistake it for wild carrot (Queen Anne’s Lace), parsley, parsnip, sweet cicely, anise, fennel, wild chervil, and caraway, as well as other plants in the parsley or carrot family (Apiaceae), such as the violently toxic western-water-hemlock, or watercress, which is in another family.
…“Misidentifying poison hemlock or other toxic plants can have truly tragic results,” says Alison Halpern, executive secretary of the Washington State Noxious Weed Control Board. “Learn from an expert before foraging for wild plants, and if you think you have poison hemlock on your property, contact your county weed board, conservation district, or WSU Extension office to learn how to safely get rid of it.”
While poison hemlock is considered invasive, the Quee Anne’s lace plant, though not native to California (and a plant that has also naturalized in the wild), is not considered invasive.
In other parts of the U.S., it may be easier to differentiate the two based on bloom periods, but in California, the flowering periods are similar: Poison hemlocks bloom from April to September, while the Queen Anne’s lace flowers from May to September.
Last summer, my grandsons and I spent time a lot of time walking around this greenbelt area (where there are also invasive Himalayan blackberries — and poison oak).
They know to stay away from poison oaks…and I’m glad they did not try to pick any of these flowers.
Unless you are absolutely sure which plant is which, it is best to treat these lovely flowers as poisonous, and to be careful of handling them.
I don’t have photos of the Queen’s Anne lace plant yet, but you can view a good collection at this USDA plant database page.
If you want to learn more about how to remove this toxic plant from your area, please contact your local agency, e.g., for Monterey County, start with the Agricultural Commissioner’s office, or see this USDA State Resource page.
The King County (Washington State) website has a section on noxious weed control. Excerpt and link below…
When digging or mowing large amounts of poison-hemlock, it is best to wear gloves and a mask or take frequent breaks to avoid becoming ill. One individual had a severe reaction after pulling plants on a hot day because the toxins were absorbed into her skin…(click here for more).
Since writing this post, I’ve noticed these plants in spots (by the roadside mostly) here in Monterey County, and I’m surprised that it is not listed on Monterey County’s weed threats.
Do poison hemlocks grow where you live?
Did you get the flower and plant confused with the Queen Anne’s lace flowers, as I did?