Poison Hemlock Is Toxic To People & Pets, And It Is Blooming All Over The U.S.

Poison Hemlock Is Toxic To People & Pets, And It Is Blooming All Over The U.S.

Poison hemlock is popping up all over the U.S. and while it looks like a cluster of pretty white flowers, it is toxic to both people and pets.

The entire plant, including stem and flowers, contains a neurotoxin that can be deadly if eaten in large quantities. It poses the greatest threat to livestock and horses who graze in fields, but is a plant you should be able to identify and avoid.

Pet owners need to be on the lookout for this invasive plant that is sprouting all over the country due to favorable weather conditions.

Where Does Poison Hemlock Grow?


The dangerous plant can be found in nearly every state.

It is native to Europe, Africa, and Asia, but is considered invasive in the United States.

While it originally was planted in gardens, it has now spread to roadside ditches, fields, and farms. The plant prefers a wet and moist environment so it is usually found near marshes and damp areas in the shade.

It blooms in the summer and can grow three to eight feet tall. The easiest way to differentiate between the different types of hemlocks is to look at the stems. Poison hemlock has a smooth and hollow stem with purple spots.

What Other Plants Look Like Poison Hemlock?

All of the following plants fall under the category of "look but don't touch".

Spotted water hemlock is a native plant that is considered the most deadly or as pet poison helpline describes it the "most violently toxic plant in the United States." It looks similar to poison hemlock with an umbrella of white flowers but just two bites can kill a human.

The stems are also smooth and hollow but the color and patterns vary. Unfortunately, it is just as widespread as poison hemlock.

Giant hogweed is an invasive plant that can grow up to 18 feet tall, hence why it is called giant. Touching or brushing against this plant may cause severe irritation to the skin and eyes, blistering rashes, permanent scarring and even blindness, according to U.S. Fish and Wildlife Service.

This plant's stem is thick with ridges and purple spots.

Queen Anne's lace is the least dangerous lookalike but can still cause problems to pets if consumed. This plant has a small reddish flower in the center of the white petals and a fuzzy stem with small grooves. It is lower to the ground, growing up to two feet tall.

Signs of Poison Hemlock Toxicity

- weakness
- drooling
- agitation
- dilated pupils
- twitching
- cardiac abnormalities
- difficulty breathing
- paralysis

If you or your pet have come in contact with poison hemlock, or anything that resembles it, and are experiencing any of the symptoms above, contact a health care professional immediately. Pet Poison Helpline is also available 24/7 and you can reach them at (855) 764-7661.


So the next time you are strolling through a field and spot a cluster of white flowers, take caution. It may be a hemlock plant that you should admire from a distance.

When in doubt, stay away from the pretty wildflower and don't allow any of your pets (dogs, cats, or horses) to eat it.

Andrea Powell

Andrea Powell is an animal enthusiast who resides in West Michigan. When not writing, she is exploring the great outdoors with her dogs and horses.

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