Water Hemlock Deadly Plants
Photo courtesy of SCCF Nursery

Water Hemlock | Deadly Plants

Water Hemlock and its close relations are the most poisonous deadly plants in North America. All parts are deadly poisonous. Even a small mouthful of water hemlock can kill an adult.

Therefore it stands to reason that ingesting even a little bit of water hemlock juice will make a person seriously ill.

So, it is best to learn to identify these plant by sight, rather than characteristics that require you to handle it or examine the roots or inside of the stem. It is so virulently poisonous that it is best to avoid handling it at all.

Most poisonings have occurred due to confusion between these poisonous plants and edible look-alikes, especially other members of the Parsley Family.

Please do not rely solely on this web page for identifying these highly poisonous plants. Consult field guides for more detailed information.

Do not handle these poisonous plants. If you do, thoroughly clean your hands immediately afterwards. Take appropriate steps to avoid accidentally ingesting any part of these deadly plants or their juice.

It is particularly important for wilderness survival enthusiasts to learn this plant, as its stems are hollow and are therefore appear to be ideally suited for use as straws. Don’t make use of this deadly plant in this way – many poisonings have occurred in this manner.

Water Hemlock
Cicuta maculata

Other common names: Spotted Cowbane

Family: Parsley Family (Apiaceae)

Distinctive features: Wet areas. Alternate twice-compound leaves; leaflets sometimes haphazard in arrangement.

Similar species:

  • Water Parsnip – very similar, except the leaves are only once-compound
  • Cowbane – Also poisonous, and closely resembles Water Parsnip.
  • Mock Bishop’s Weed
  • Bulb-bearing Water Hemlock
  • Wild Carrot (Queen Anne’s Lace) – but this plant grows in dry areas
  • Other members of the Parsley Family.

Height: 3-6 feet tall

Flowers: Small white flowers in a flat or rounded umbel (an umbrella-shaped cluster) 2-5″ wide. Individual flowers about 1/8″ wide, have 5 petals and 5 stamens.

Leaves: Alternate compound leaves with lance-shaped leaflets, pointed, with numerous teeth. Note the sometimes multiples of leaves giving rise to a somewhat haphazard arrangement of leaves along the leaf stem. Sometimes doubly compound or lobed. Sometimes tinged with red. Up to about 4″ long, 1.5″ wide. The veins on the leaflets end at the notches between the teeth (this is unusual in plants).

Stem: Branching, smooth & stout, often mottled or solid purple. Hollow. Lower part of stem chambered. Roots have fat tuberlike branches.

Habitat: Wet open areas such as marshes, along shores, and sometimes open swamps.

Longevity: Perennial

The whole plant. Note its somewhat open ragged look.

deadly plant 1


water hemlock

Another look at the leaves.

poisonous plant

These leaves are a bit abnormal – they are “chunkier” than usual.

water hemlock 2

As always with plant identifications … watch out for the aberrant individuals.

water hemlock flower

Flower umbel.

Note: this is part of the article. Please visit TrackerTrail to view the entire article.

Walter Muma runs TrackerTrail.com, a highly comprehensive skills website. Please check it out to learn about all sorts of wilderness skills, including more deadly plant articles! Photo courtesy of SCCF Nursery.


  1. Jeff Killen

    How is it possible to rapidly differentiate between hemlock and Queen Ann’s Lace,
    or wild carrot.

    I live in southern Oregon at present, but lived most of my life in Southern California.
    There are plants growing in a field across the road from my mobile home park. I
    thought they are Queen Ann’s Lace, but doing research on hemlock, I am not so
    sure. There are a number of plants growing in the yard where my mobile home is
    located that have similar leaf appearance. Some of the (?) Queen Ann’s lace were
    even growing on my lot last year. I pulled them all out.

    Thank you for time and attention.

    • Queen annes lace has one small purpleish flower in the center of the flower “plate”

      • Jeff Killen in reply to alice

        Thank you for the info, I will be on the lookout for that.

    • I don’t know how old this post is, but here’s my advice: if you’re not sure, don’t handle it. It is a dangerous business when dealing with look-a likes and I have managed to poison myself a few times, though not with something as deadly as hemlock. One of the few distinctions for Queen Ann’s Lace is the purple flower that blooms for part of the year, as mentioned above, but this flower is not always present

  2. Brandon

    Oh, I forgot to mention that the flowers of a water hemlock are grouped much more loosely than the flowers of Queen Anne’s Lace. The flowers will be grouped in small, scattered bundles, while QAL usually has large clusters of flowers.

  3. neeka

    brandon is absolutely right, the purple flower isn’t always present. but QAL has a hairy stem. i always remember by saying the queen has hairy legs :-) i hope this helps.

  4. Cait

    We have “water hemlock” growing everywhere around our house, near our creek and it is spreading throughout our lawn, garden, fields and orchard. Help! We need to stop these incidious plant monster before it completely takes over our property and beyond! Any suggestions and/or advice as to its destruction would be greatly appreciated. Thanks!

  5. Queen Anne’s Lace has a hairy stem, Water Hemlock does not. Queen Anne’s Lace roots also smell very much like the carrot that it is.

  6. Gay Muse

    I live in central ky , I lost 3 cows to hemlock poisoning in 2012 and one in 2013.
    Hemlock grows in all four corners of our farm and lines both sides of the Paducah and Louisville railroad that borders our property. Best thing we have used(it is ongoing battle, is hoe, 2-4d herbicide and crossbow brush killer., bushhog.

    • i have both queen anns lace and water hemlock on my property. i know queen anns well but was baffled by the hemlock.i have been mowing the edges of my property and got into some of this invasive plant.my arms got all broke out with pussy pimples and it itches like mad. therefore when i looked it up . i saw your comments.queen annes is a very tite and beautifully symetrrical flower. it doesn’t always have the purple center. it smells very fragrant like carrot tops. the water hemlock plant itself has no loud smell but the flowers have an almost overpowering fragrance.the stems are very smooth and it grows really tall.its such a fast grower it’ll far outreach anything you plant with it. it sprawls over itself and becomes a pain to erradicate. hopefully this helps out anyone clearing their property. wear full sleeved clothing and pants and gloves to handle as i,ve found out the hard way. thanx.

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