The Cambrian

It was Socrates’ undoing, and it’s all over the Central Coast

Hemlock is seen growing near the Cambria Vineyard Church on the 1600 block of Main Street.
Hemlock is seen growing near the Cambria Vineyard Church on the 1600 block of Main Street.

Gardeners and foragers beware: You may be tempted by a pretty plant that looks a lot like its well-known, equally fluffy-headed edible cousin — the fennel (anise) herb.

The similar plant can be lethal, however. It’s the infamous poison hemlock, which was in the toxic mixture drunk by the philosopher Socrates before he died in 399 B.C.

How do you tell the difference between fennel and poison hemlock?

According to wildflower experts, there are plenty of distinctions.

First and foremost, look at the stems. If there are blotches, speckles or bits of purple on the hollow, hairless stem, it’s poison hemlock.

Also, says “fennel foliage is thready,” looking somewhat like dill, “whereas hemlock leaves are triangle shaped and lacy … Fennel has yellow flowers while hemlock has white flowers. If you bruise a hemlock leaf or sniff a flower it smells kinda nasty, whereas all parts of the fennel taste and smell deliciously like anise/licorice.”

Local botanists say both plants have grown for years on the North Coast and throughout various parts of California and the U.S. But this year, thanks to record rainfall along the Central Coast, poison hemlock may be popping up in places where it might not have been noticed, or even grown, before.

It often mixes in with cilantro in gardens, according to Los Osos botanist John Chesnut. “The rich soil favored for cilantro cultivation is good habitat for hemlock, and the two can be confused in the vegetative state.”

It’s never very difficult to find. It likes the coastal canyons, with more moist conditions.

Doc Miller, botanist

And wherever the ubiquitous weed is growing, according to Doc Miller, a botanist and local wildflower expert, the poison hemlock this summer is likely much larger than it’s been in the past few years, especially during the recent prolonged drought.

“Everybody is robust,” he said in a July 19 phone interview. “What we’ve seen with regeneration after the Chimney Fire in conjunction with the rainfall, is tremendous size on almost any and all annuals. I wouldn’t be surprised if someone came across an aconitum (poisonous monk’s hood) half-again higher overhead.”

Miller’s exceptionally familiar with post-Chimney Fire conditions: That blaze destroyed his cabin home.

“It’s never very difficult to find” poison hemlock here, he said. “It likes the coastal canyons, with more moist conditions. It’s uncommon to find it over the hill” in hot, dry summer climates.

That may be why more people here are noticing the attractive but potentially deadly plant that he said flourishes “in disturbed soil situations,” such as vegetable gardens and washed-out creek beds.

Covering garden soil as much as possible will discourage poison hemlock growth, he said. “It needs the purchase of raw soil to grow from.”

Don’t go there

Miller, Chesnut and wildflower expert Holly Sletteland are emphatic that people should never, ever forage on private or public lands if they don’t have legal permission to do so. According to local rancher/historian Dawn Dunlap, it’s a misdemeanor to trespass on land where food is being grown, such as a cattle ranch, vineyard or farm.

But what should people do if they find something they suspect is poison hemlock on their own property?

One school of thought, espoused by such entities as the California Native Plant Society, says a nonnative poison hemlock plant should be removed and discarded with other greenwaste.

Miller prefers to let it be. “Running amok, removing all greenery, taking it back down to raw mineral soil” isn’t good for the environment, he said. “You’re inviting in every wild, rank seed there is.”

He said poison hemlock is “pollinator attractive,” which means the plants appeal to native bees and butterflies.

Poison hemlock “does fit into our altered ecosystem,” Miller said. Just don’t ingest it.

Friends of the Fiscalini Ranch Preserve

Sletteland, project manager for the Fiscalini Ranch Preserve, said in a series of email interviews that “we don’t have a lot of poisonous plants on the ranch that I’m aware of. Besides hemlock, the only other one I can think of are the fruits of nightshades, both purple and white.”

Nightshade leaves are eaten by deer without problems, she said, “and the flowers are beautiful and provide food for pollinators.”

However, poison hemlock is toxic for animals, she said.

Many other plants “are mildly toxic, such as yarrow, buttercup and acorns, if they aren’t treated first. Similarly, plants like stinging nettle, which actually is edible, is something most people need to watch out for, as a brush with your skin will cause a painful rash. Ditto for poison oak. We also have plants that can be painful to step on, especially for pets, like spiny cocklebur and prickly coyote thistle.”

Poisonous and toxic

Chesnut said, “many of the most common poisonings are from plants that are edible at some stage and seriously dangerous at others. And garden introductions,” also referred to as “volunteer plants.”

He said most dangerous to the amateur are plants “that are poisonous at one stage, such as elderberry, or easily confused with non-toxic, such as the death camas … both of which are in native landscapes locally.”

So, unless you’re an expert, just look, photograph and appreciate those pretty wildflowers and weeds. But, to paraphrase the title of a best-selling 1957 book and spinoff TV series in the 1960s, please don’t eat the poison hemlock.

Poisonous plants

For details and lists of noxious plants and more than 370 poisonous and other noxious plants, go to Of course, the poison hemlock plant is not related to the usually gigantic, cone-bearing hemlock pine trees found primarily in summer-humid, mountainous areas from Northern California to Alaska, Idaho, Montana and eastern Canada.