Poisonous Plants: Spotted Water-hemlock

Photo of Spotted Water-hemlock

I believe every plant has gifts to offer. Some plants are nourishing human foods or medicines, others provide habitat for spiders, pollen for pollinators, or forage for herbivores, while others provide gifts we may not yet recognize. I'd like to suggest that the notorious, native perennial Spotted Water-hemlock (Cicuta maculata) gifts foragers with the reminder to take proper identification seriously.

Spotted Water-hemlock is said to be New England's most toxic plant species. Lee Allen Peterson writes of C. maculata: "Warning: Our deadliest species. A single mouthful can kill."* A plant this toxic is surely worth getting to know, if only so we learn who not to forage. Spotted Water-hemlock has tiny, 5-petaled, white flowers in 2-4" wide double umbels, twice or thrice pinnately-compound leaves with coarsely toothed leaflets, and a multi-branched, smooth, purple stem.

The toxicity of this species and other members of the Carrot (Apiaceae) family requires foragers to exercise caution when collecting any of the edible members of this family. Care should also be taken not to confuse Spotted Water-hemlock with Black Elderberry, a shrub in an unrelated family (Adoxaceae). Though the two plants have many clear differences, their flowers from a distance may appear similar, and they may grow near each other in roadside ditches or on the edges of wetlands.

Powerfully toxic plants like this one are why I caution against "identifying" a plant based on a single field mark or an apparent photographic match, and instead stress the importance of learning to use a reliable field guide or trusted online resource to key out unfamiliar plants. Skipping this crucial step could result in more than just discomfort. (To view the following images in full-size, click here.)

*A Field Guide to Edible Wild Plants of Eastern and Central North America (1977), p. 42.

6 thoughts on “Poisonous Plants: Spotted Water-hemlock”

  1. Thanks for this, Josh, and for all the great photos of it’s field marks. What a gorgeous plant! Could you talk a little about it’s fruit, for those of us thinking of foraging for elderberries for the first time this year, for comparison’s sake?

        1. Some more questions for you, as we had a suspected run-in today in which the little one touched a seed head before eating lunch. (We watched her very closely and it’s been about 11 hours now, so I’m starting to relax.) A few of the sources I’ve found online say it has purple blotches on its stem, whereas your photos show it having a solidly purple stem. Does the purple vary? Do the green seeds resemble wild sarsparilla seeds? And to my eye, the plant we studied mostly matches the leaf shape (sans the distinct purple edges), the “fireworks” shaped seed head, the overall habit, the purple stem, only it had smooth stems everywhere except for a few inches from the ground, where it was covered in profuse, brownish hairs.
          Any ideas?

          1. It sounds like you’ve found Aralia hispida (Bristly Sarsaparilla). Could the “hairs” at the base have been “bristles”? Was your plant growing in a dry place? If I’m right, you should notice the now-green fruit will soon turn a plump dark blue. See if this matches: https://gobotany.newenglandwild.org/species/aralia/hispida/

            You also asked about stem color. The plants I’ve checked have all had stems similar to those I photographed: not spotted with purple, but rather an overall purplish color. In any case, Spotted Water-hemlock doesn’t have a bristly or hairy base.

            The “fireworks” shaped seed head you describe (if your plant is Bristly Sarsaparilla), is called an umbel. Spotted Water-hemlock flowers and fruits in double-umbels (like many little umbrella clusters arising from a larger umbrella).

            I don’t believe touching Spotted Water-helmock is enough to do harm, but I suppose it’s better safe than sorry.

            Good job looking closely at your plant in question. I hope my feedback helps settle your concerns.

  2. Yes, you’ve got it! Bristly Sarsparilla looks just like the plant we saw! That explains why its seed heads looked exactly like wild sarsparilla seed heads. Thank you!
    Yes, they could be bristles. And I didn’t note if it was a particularly wet or dry area.
    Thank you again, for solving the mystery and giving me immense peace of mind! 🙂
    There’s nothing like a suspected run-in with a highly toxic plant to sharpen one’s observation skills!

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