Poison Hemlock: Lovely and Lethal

Poison Hemlock Forest in Bloom

These delicate and graceful plants might tempt you to pick them for a bouquet. Don't do it. This is deadly poison hemlock. For a closer look, please click the picture.
These delicate and graceful plants might tempt you to pick them for a bouquet. Don't do it. This is deadly poison hemlock. For a closer look, please click the picture. | Source

Toxic Parts of Poison Hemlock

Poison hemlock is easiest to recognize when it's blooming, as it is in this picture, during spring and summer. The white flower clusters appear as upside-down umbrellas. Click to enlarge pictures.
Poison hemlock is easiest to recognize when it's blooming, as it is in this picture, during spring and summer. The white flower clusters appear as upside-down umbrellas. Click to enlarge pictures. | Source
In this picture you see the purple-spotted stem and a good view of the leaves. You can also see the buds of the flowers forming. Please click for a closer view.
In this picture you see the purple-spotted stem and a good view of the leaves. You can also see the buds of the flowers forming. Please click for a closer view. | Source
This is the root of a small poison hemlock plant. The larger the plant the larger the taproot, which may be divided as this one is. If you get close you will notice a musty or sickeningly sweet smell that will repel you. This is no wild carrot.
This is the root of a small poison hemlock plant. The larger the plant the larger the taproot, which may be divided as this one is. If you get close you will notice a musty or sickeningly sweet smell that will repel you. This is no wild carrot. | Source

Getting to Know Poison Hemlock

Deadly poison hemlock is so beautiful it might tempt you to tolerate it on your property. Its fern-like leaves and delicate white flowers are similar to those of Queen Anne's lace, a plant I've never seen except in books. Its leaves also slightly resemble those of wild carrot, parsley, parsnip, and fennel. That's another reason you don't want it near your garden. It just might cross pollinate with edible plants and cause problems. Experts I've talked to won't commit themselves on these effects one way or another.

All parts of this plant are poisonous. Consuming even a small amount of any part of the plant can be fatal. This is why you must make every effort to eradicate it from your yard if you have any children around who might be tempted to put it in their mouths. The best time to get rid of it is when it's very small and the ground is soft after a rain. It's taproot is long and if you grab the top to pull, the top will often separate, leaving the root in the ground. I tried pulling a bunch of them yesterday under such ideal pulling conditions, and only managed to get the root on one of them. I probably need to go back and use a fork spade to get the roots. When you finally get them from the ground, you will want to bag them up and throw them away. Do not compost them with the other weeds. When you finish weeding, remember to wash your hands thoroughly with soap -- even under the nails. Of course, if you're smart, you'll wear gloves. I was just impulsive and didn't want to go back after them.

Through the rest of this hub I'll be showing you lots of pictures of poison hemlock so that you will be able to identify it during any season. The rule of thumb is, if you're not sure what a plant is, don't take chances. You'll never be killed by leaving a plant alone.

Poison Hemlock Growing in Stump

As you see, poison hemlock will grow nearly anywhere it has enough moisture to germinate its seeds. The small seedlings grow in the stump, and their larger cousins grow beside the stump on the ground. Taken at Lawrence Moore Park, Paso Robles.
As you see, poison hemlock will grow nearly anywhere it has enough moisture to germinate its seeds. The small seedlings grow in the stump, and their larger cousins grow beside the stump on the ground. Taken at Lawrence Moore Park, Paso Robles. | Source

Medium size seedlings.

Taken at Lawrence Moore Park, Paso Robles. You can see what appears as a green carpet under the dead poison hemlock plants. This is a lush carpet and appears from a distance like mounds of green.
Taken at Lawrence Moore Park, Paso Robles. You can see what appears as a green carpet under the dead poison hemlock plants. This is a lush carpet and appears from a distance like mounds of green. | Source
Taken at Lawrence Moore Park, Paso Robles.  These plants are a bit closer so you can see their leaves better. They look a lot like small ferns.
Taken at Lawrence Moore Park, Paso Robles. These plants are a bit closer so you can see their leaves better. They look a lot like small ferns. | Source

Baby Poison Hemlock Seedlings

I hope you will recognize the frilly, fern-like poison hemlock here, as opposed to the broader leaf wild mustard seedlings. You will notice the poison hemlock seedlings look a lot like parsley, with which you might confuse it.
I hope you will recognize the frilly, fern-like poison hemlock here, as opposed to the broader leaf wild mustard seedlings. You will notice the poison hemlock seedlings look a lot like parsley, with which you might confuse it. | Source
This is a baby poison hemlock forest. This is the stage at which you should get out your hoe and dispatch the tiny plants. This has the potential of becoming a 6-10 foot lethal forest.
This is a baby poison hemlock forest. This is the stage at which you should get out your hoe and dispatch the tiny plants. This has the potential of becoming a 6-10 foot lethal forest. | Source
This is a close-up of the above seedlings. Get a good look at their tiny, but well-developed leaves.
This is a close-up of the above seedlings. Get a good look at their tiny, but well-developed leaves. | Source

Seedlings

Although poison hemlock seeds can travel, you will find most of them near where poison hemlock bloomed and died the year before. Poison hemlock is a biennial plant. The seeds germinate the first year. The second year the flowers grow and go to seed. Then the plants die in the heat of the summer -- at least that's been my experience.

If you walk around my county in autumn, you will often see forests of dead hemlock. After the rains come, you will see the ground turn green under these forests. The frilly leaves that emerge indicate poison hemlock. You might also see some seedlings with white veins in their spiny edged leaves. Those would be milk thistle, which often grows in close proximity to poison hemlock. Just as the plants are often found growing together, so do their seedlings.

I will show you a lot of pictures of the seedlings, some mixed with those of other plants as they occur in nature. I will identify what I can. You will notice that the smallest seedlings greatly resemble parsley. I always buy a parsley seedling and keep it in a pot, since I know then where the parsley is supposed to be. I think I have enough experience to know the difference now between the two, and, of course, the differences become more evident as the plants grow older. One big difference is that poison hemlock seems to germinate easier than parsley, and my lack of success at growing parsley from seed is the real reason I buy the seedlings.

You will notice that I took a lot of these pictures at Lawrence Moore Park in Paso Robles, California, which is adjacent to the Salinas River Trail. It is a riparian habitat and an oak woodlands. Poison hemlock thrives in either environment, but it will also do very well in your garden or open fields if it gets established during the rainy season. They seem to make no effort to eradicate this plant. It also grows anywhere the other weeds do, so you'd best learn to recognize it and help your children to the same, since they will find it growing nearly anywhere in wild areas of public land -- even if they are city parks.


Please remember that you can make even the largest pictures bigger by clicking them to see full size. You can observe the details more easily that way.

Poison Hemlock in the Wild

Taken at Lawrence Moore Park, Paso Robles. Here the poison hemlock grows along the fence by the Salinas River.
Taken at Lawrence Moore Park, Paso Robles. Here the poison hemlock grows along the fence by the Salinas River. | Source
Taken at Lawrence Moore Park, Paso Robles. Here it's growing right by the trail.
Taken at Lawrence Moore Park, Paso Robles. Here it's growing right by the trail. | Source
Taken at Lawrence Moore Park, Paso Robles. Here we see poison hemlock growing along the river banks.
Taken at Lawrence Moore Park, Paso Robles. Here we see poison hemlock growing along the river banks. | Source
Taken at Lawrence Moore Park, Paso Robles. Although the poison hemlock here is thigh high on this couple walking on the path next to it, in a few weeks it will be taller than the people.
Taken at Lawrence Moore Park, Paso Robles. Although the poison hemlock here is thigh high on this couple walking on the path next to it, in a few weeks it will be taller than the people. | Source
Taken in my own yard in mid-November. These new poison hemlock seedlings germinated from seeds dropped by parents across the fence. The poison oak is also creeping across.
Taken in my own yard in mid-November. These new poison hemlock seedlings germinated from seeds dropped by parents across the fence. The poison oak is also creeping across. | Source

A Reading List

Plants of San Luis Obispo: Their Lives and Stories
Plants of San Luis Obispo: Their Lives and Stories

This new book in my collection focuses on the native plants that grow in San Luis Obispo County where I live, but many of the plants are found in other parts of California and even in other states. It has color illustrations of the most common plants, along with some information on how to identify them. It will tell you if a plant is poisonous, and maybe if the plant is also edible. The book is organized by the habitats in which the plants grow.

 
Wicked Plants: The Weed That Killed Lincoln's Mother and Other Botanical Atrocities
Wicked Plants: The Weed That Killed Lincoln's Mother and Other Botanical Atrocities

I have read other books by Amy Stewart, and they have always been entertaining, as well as informative. This one is going on my wish list. I did check to be sure it covers poison hemlock. It does, along with other wicked and disgusting plants.

 
The North American Guide to Common Poisonous Plants and Mushrooms
The North American Guide to Common Poisonous Plants and Mushrooms

This one is also going on my wish list, since it is said to be going out of print. I am finding my collection of books about weeds leaves way too much out. This was said to be the cadillac of field guides to poisonous plants by the customer reviewers. I'm going to buy it before it's too late.

 
Nature's Garden: A Guide to Identifying, Harvesting, and Preparing Edible Wild Plants
Nature's Garden: A Guide to Identifying, Harvesting, and Preparing Edible Wild Plants

Poison hemlock isn't edible, but the wild carrot is. Thayer spends seven pages showing you how to tell the two apart. The first five of these pages have pictures of the seedlings, roots, leaves, stems, and flower patterns. I could not show you these differences, since I don't have access to wild carrots here. There is also a full-page chart that explains how to tell the two plants apart.

Besides the comparison between these two plants, the book has detailed descriptions of over 40 plants, most edible with some look-alikes, and over 400 color plates. This is the first book on edible wild plants that had actually helped me identify them without a doubt. I highly recommend it.

 

Dry Poison Hemlock Forests

These blooming poison hemlock plants on the left will soon look like the ones on the right who will not live much longer. They will soon look like the plants below. Taken from my property.
These blooming poison hemlock plants on the left will soon look like the ones on the right who will not live much longer. They will soon look like the plants below. Taken from my property. | Source
Taken at Lawrence Moore Park, Paso Robles.
Taken at Lawrence Moore Park, Paso Robles. | Source
Taken at Lawrence Moore Park, Paso Robles. You can also see the dry milk thistle beside the hemlock here. Be sure to read warning in text capsule below.
Taken at Lawrence Moore Park, Paso Robles. You can also see the dry milk thistle beside the hemlock here. Be sure to read warning in text capsule below. | Source

Even the Dead Can Be Deadly

Poison hemlock stems are hollow. Because of this, boys have passed dead forests such as those above and decided to make whistles or flutes from the hollow stems. They died. The poison remains in the dead stems. It only takes a little bit to kill.

Poison Hemlock Out of Control

Taken at Lawrence Moore Park, Paso Robles. Talk about intrusive! How would you like this companion while trying to each lunch on this bench?
Taken at Lawrence Moore Park, Paso Robles. Talk about intrusive! How would you like this companion while trying to each lunch on this bench? | Source
Here the poison hemlock and some of its favorite companion, milk thistle, are creeping up on the park bench.
Here the poison hemlock and some of its favorite companion, milk thistle, are creeping up on the park bench. | Source
Taken at Lawrence Moore Park, Paso Robles. Here the blooming poison hemlock begins to tower above the top of the bench back.
Taken at Lawrence Moore Park, Paso Robles. Here the blooming poison hemlock begins to tower above the top of the bench back. | Source
Taken at Lawrence Moore Park, Paso Robles. Here the fence-high poison hemlock, is preparing to grow even higher. Looks like someone might finally be spraying to get rid of it around the bench.
Taken at Lawrence Moore Park, Paso Robles. Here the fence-high poison hemlock, is preparing to grow even higher. Looks like someone might finally be spraying to get rid of it around the bench.

Poison Hemlock Mixes Well with Friends

One of its best friends is milk thistle, with its beautiful milky veins in its large and prickly leaves. Taken in my back yard.
One of its best friends is milk thistle, with its beautiful milky veins in its large and prickly leaves. Taken in my back yard. | Source
Here the same friends huddle against a fence. Taken at Lawrence Moore Park, Paso Robles.
Here the same friends huddle against a fence. Taken at Lawrence Moore Park, Paso Robles. | Source
This scene from my garden area May 30 shows what can happen after lots of rain if you don't get the weeds right away. Fortunately my husband hired someone to help so we could have a garden that year. Click to see the purple thistle flowers enlarged.
This scene from my garden area May 30 shows what can happen after lots of rain if you don't get the weeds right away. Fortunately my husband hired someone to help so we could have a garden that year. Click to see the purple thistle flowers enlarged. | Source

Know Your Enemy

I hope by now you know poison hemlock well enough to leave it alone. It would also not be a good idea to sit on that park bench when the the hemlock is blooming, since some people react to its pollen. All parts of the plant are poison, and that would include the pollen, I think, if you breathe it in. I try to keep my distance when it's blooming.

You have probably noticed poison hemlock likes to be around milk thistle if you looked at the pictures just above this. You can read more about milk thistle in my related hub. It will also give you some additional pictures of the two friends together when in bloom. May you remain happy and healthy in the outdoors by keeping your distance from both these plants.

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22 comments

Eiddwen profile image

Eiddwen 4 years ago from Wales

A brilliant hub,so much well presented information and the photos are beautiful.

Your obvious hard work has certainly paid off!!

I vote up and wish you a great day.

Eiddwen.


akirchner profile image

akirchner 4 years ago from Central Oregon

Totally well presented and lovely pictures of such a deadly plant. I'd worry like heck about having this around especially walking my dogs.

I imagine they would be tempted to chomp on it like they do grass though I would hope that dogs (and other animals) would have the instinct to leave it alone?

Amazing how so many 'bad plants' are so in charge that they take over everything. Gotta love the idea of sitting in the middle of it on a bench....no thank you. I'd be afraid someone might slip me some for good measure to shut me up for good~ haha

Great job, Barb - voted up and everything in between~


WannaB Writer profile image

WannaB Writer 4 years ago from Templeton, CA Author

Eiddwen, this is the sort of work I enjoy. If what I write might prevent one death, it will be well worth the effort. Thank you for your comment. I'm blushing.


WannaB Writer profile image

WannaB Writer 4 years ago from Templeton, CA Author

Audrey, I'm nopt sure if this is equally deadly to dogs, but I wouldn't take chances. Let's hope God does give animals an instinct that protects them from poisonous plants.

I actually did sit on that bench because it was the only place to sit when I had to change my camera batteries. The plants weren't blooming yet then. I've actually been around the plants when they were blooming, with no ill effects, before I read that the pollen can be harmful. Since then I've tried not to work around them.


ksg 4 years ago

I'm glad I didn't grab any of this, here I thought it was Queen Anne's Lace. I will not pick unless I know for sure now. Thank you.


WannaB Writer profile image

WannaB Writer 4 years ago from Templeton, CA Author

ksg, I first thought it was Queen Anne's Lace, too, but asked our weed abatement man about it. He set me straight.


Becky Katz profile image

Becky Katz 4 years ago from Hereford, AZ

I saw your pictures and thought it was Queen Anne's lace. There is a way to tell them apart but you need to get close to do it. The stems on the Queen Anne's lace is fuzzy. The site I looked it up on said that the saying to keep it in your mind better is "Queen Anne's leg are hairy." I had to laugh over that. I love Queen Anne's lace and refuse to let my sons mow it down. I love to see it bloom. I do make sure that it is before I tell them not to mow it. They are related and the Queen Anne's lace is the wild carrot.


WannaB Writer profile image

WannaB Writer 4 years ago from Templeton, CA Author

Becky, thanks for that hint for telling them apart. The first time I ever saw it, I thought it might be Queen Anne's Lace. One of the local farmers set me straight. I'll have to remember that line.


DzyMsLizzy profile image

DzyMsLizzy 4 years ago from Oakley, CA

Very informative, indeed. I wonder if the hemlock is a contact irritant or poison as well, as with the poison oak/ivy/sumac trio?

Voted up, useful, awesome and shared!

(By the way--there seems to be some kind of glitch with HP's "see larger" photo utility--when clicked, they are being displayed the same size, and sometimes actually smaller than the photos within the article.)


MarleneB profile image

MarleneB 4 years ago from Northern California, USA

Wow. It looks like poison hemlock is a very hearty weed. I read the article on milk thistle, as well. My neighbor has what looks like poison hemlock growing through the fence on to my side. I'm going to print one of your pictures and match it up with that plant to be sure. I never even thought about the idea that we could be at danger if we were to breathe in the pollen. I'm almost afraid to go outside now. What an informative hub.


WannaB Writer profile image

WannaB Writer 4 years ago from Templeton, CA Author

DZYMsLizzy, have pulled poison hemlock gloveless without a rash developing, but some literature suggests it can irritate the skin. What is important is to wash your hands very well with soap if you have touched any part of the plant before your hands come in contact with food or a surface where food is prepared. I'm sorry to hear there's a glitch with the pictures. One no longer has the option to show the pictures at original size when making new hubs, so maybe the functionality of earlier hubs has been disabled. I'm sorry if this is the case, because it means having to show more pictures of normal size instead of half-width alongside the text.


DzyMsLizzy profile image

DzyMsLizzy 4 years ago from Oakley, CA

Thank you for the quick info. Luckily, (knock wood), we've not seen any of this stuff on our property.

As for the pictures...HP has of late had some issues with "fixing" things that were not broken.... :-(


WannaB Writer profile image

WannaB Writer 4 years ago from Templeton, CA Author

Mariene, I wouldn't worry about pollen coming from the neighbor's yard. You just shouldn't get too close to it when it's in bloom. My property has been full of it and I've even pulled it up by the roots without harm. My entire town is full of this stuff and you really can't escape it here, but allergies aren't any worse than from the trees and other weeds in bloom.


WannaB Writer profile image

WannaB Writer 4 years ago from Templeton, CA Author

DzyMsLizzy, I'll hope you don't get it on your property. I have a house very near (about three blocks) from where forests of this stuff and the milk thistle grow by the river. So far my property there has not been touched by either. Living n a residential neighborhood without a lot of wild places helps. I live in the country and you will find both these weeds growing along all the country roads and on rural properties like ours. It's as common as wild mustard. As to HubPages fixing things not broken, I'm hoping for the best.


StephanieBCrosby profile image

StephanieBCrosby 4 years ago from New Jersey

Now you have me concerned. I think I had a ton of this growing in my yard last season. I do not see it this year though. And this would fit with the biennial cycle you discussed in the other article. We got so many comments from neighbors about our beautiful white flowers that looked like bunches of baby's breath from a distance. And it figures, it was the only plant I did not buy. So I figured it was something that went to seed from all the bird seed mixes. I have to look into this more as I have two small children. But, as I said, I don't see the plants this year, thank goodness.


frogyfish profile image

frogyfish 4 years ago from Central United States of America

Came here after reading your 'Prickly' hub about milk thistle. After reading this, what I thought might be hemlock, does not get that tall...could it be because of heat and lack of water in this region as compared to CA?

Informative hub again! Thank you!


WannaB Writer profile image

WannaB Writer 4 years ago from Templeton, CA Author

Stephanie, it's funny they wouldn't have reproduced. Did you get rain? They come with the spring rains here from the previous year's seeds. They normally live for two years and reproduce the second year. We get babies every year, maybe from different generations. it's hard to believe they would have left you in peace. What did you do with last year's plants when they died? Or did you pull them out before they died?


WannaB Writer profile image

WannaB Writer 4 years ago from Templeton, CA Author

Frogyfish, that might be. Did the stems have purple splotches? That's one characteristic of poison hemlock. We don't water ours -- they get it from the rain. They prefer a bit of moisture. I would suspect they would not do as well in poor soil and dry, hot conditions.


cclitgirl profile image

cclitgirl 4 years ago from Western NC

Awesome pictures and thank you for such clear identification tips. I think I have this all over my yard (gasp!) - I'm going to go out and have a look. :) Thank you so much for sharing this information.


WannaB Writer profile image

WannaB Writer 4 years ago from Templeton, CA Author

cclitgirl, I do hope it's not all over your yard -- especially if you have children. Before you rip it all out or spray it, check the stems to see if they are hairy (Queen Anne's Lace) or smooth with purple spots (poison hemlock). I really recommend spraying, much as I hate it, for poison hemlock, because that kills the root, too. For sure you want to get the tops off before they bloom, but it sounds like it's too late for that. Remember not to compost it. Treat it like poison oak to dispose of -- bag it tightly and put in trash.


StephanieBCrosby profile image

StephanieBCrosby 4 years ago from New Jersey

Hello again. I think I cleared out most of the bed for the next season because I planned on laying down a tarp to keep weeds from growing. But I never got that far. I just remember pulling almost anything that was dead or I thought was a weed at the end of the season, especially since poison ivy was growing in the same area.


WannaB Writer profile image

WannaB Writer 4 years ago from Templeton, CA Author

Stephanie, laying down that tarp was a clever idea. Every year I tell myself I will lay down papers in the fall, but I never seem to get it done before the rainy season starts. I'd never though about a tarp -- so much easier.

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    Barbara Radisavljevic (WannaB Writer)596 Followers
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    Barb's hobbies are photography and studying nature. She gardens and takes photo walks to explore nature and capture it on camera.



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