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Poisonous Garden Plants: Iris, Azalea, and Hydrangea

Diana was a Member of the Royal Horticultural Society. She & her family all love gardening. She enjoys photographing & painting plants too.

Are You Aware That the Iris, Azalea and Hydrangea Plants Are All Considered to Be Toxic Plants?

Most people know about the very poisonous plants like mistletoe, deadly nightshade and poison ivy, but as a safety precaution, it is important that you should also know about other toxic plants like iris, azalea and hydrangea which might not necessarily kill, but could still poison someone and make them feel very ill.

Paradoxically, many potentially harmful plants, including Irises, are also considered to have healing properties.

Danger Alert! Iris, Azalea and Hydrangea Are All Poisonous Plants

Danger Alert! Iris, Azalea and Hydrangea Are All Poisonous Plants

Poisonous Plant Iris at Chelsea Flower Show

Poisonous Plant Iris at Chelsea Flower Show

1. Poisonous Plant: Iris (Also Known As Flag)

The bulbs of irises are poisonous, possibly only mildly so.

Irises contain the potentially toxic compounds irisin, iridin, or irisine.

Poisonous Parts:

Bulb, leaves, and stem

Symptoms of Poisoning:

The gastrointestinal tract may become affected by the glycoside iridin, causing nausea, vomiting, abdominal pain, diarrhoea, and fever. Also Iris can cause skin irritation or dermatitis.

Medical Uses:

In ancient times Egyptians would grind together salt, small doses of dried iris, mint and pepper, to make a substance for cleaning the teeth. Recent research has shown that the iris really does have beneficial properties and a preparation made from iris is effective in combatting gum disease.

Poisonous Plant Azalea

Poisonous Plant Azalea

2. Poisonous Plant: Azalea

Are azaleas poisonous to humans? Yes they are!

Azaleas are a sub-species of the rhododendron family. Azaleas and rhododendrons are ornamental shrubs, which flower in Spring. They are grown for their clusters of spectacularly bright and showy flowers and evergreen foliage.

Unfortunately they have potentially toxic leaves and flowers and even the honey from their flowers can be poisonous.

Poisonous Parts:

Their flowers and leaves contain glycosides, but particularly andromedotoxin. This is a volatile resin which, if ingested, burns the mouth, and thus usually discourages potential victims from consuming dangerous quantities of the leaves.

Symptoms of Poisoning:

The human digestive tract is capable of breaking down small doses of andromedotoxins into harmless compounds, so human fatalities from eating these plants are rare. However, victims who consume a lot may suffer from nausea, vomiting, abdominal upset, and low blood pressure.

People who regularly eat affected honey may also suffer similar chronic symptoms .

Treatment:

Detoxification and fluid replacement by doctors.

Poisonous Hydrangea (Botanical Name Hydrangea Macrophylla).  The One Above Is From the Lacecap Species

Poisonous Hydrangea (Botanical Name Hydrangea Macrophylla). The One Above Is From the Lacecap Species

3. Poisonous Plant: Hydrangea (Hydrangea Macrophylla)

Who would have thought that hydrangeas are poisonous plants?

Hydrangea (botanical name: Hydrangea Macrophylla) is a plant which is poisonous to humans, although not usually deadly.

Poisonous Parts:

Leaves, buds, flowers, and bark.The poisonous component is Hydragin.

Symptoms:

stomach pain, nausea, vomiting, sweating, diarrhoea, lethargy and, in severe cases, more serious problems like labored breathing, convulsions and coma.

Sensitive people may develop contact dermatitis from handling the plants.

Treatment:

Doctors will try to replace your fluids, help you breath more easily and administer drugs to bring back your normal heart rhythm.

If You Have Irises, Azaleas Or Hydrangeas in Your Garden, Don't Panic

It doesn't follow that if you have them in your garden you will be poisoned--merely that they might affect you

I would just mention that I have all these plants in my garden, and have never experienced any adverse effects, and neither has my cat, or anyone I know.

So what can we conclude from this?

Have I been extra careful?

No--until I started researching, I had no idea that these plants were poisonous. I've been aware since I was a child that plants with white sap, like poinsettias, are poisonous, and I learned the hard way (when my fingers turned black and burnt) that hellebores are poisonous, but these particular beauties--never!

Have I just been lucky?

I will have to answer yes to that. So what do we put my good fortune down to?

All I can say is that I have planted them, touched them, nurtured them and even pruned them without developing any of the symptoms described above. Maybe some people are just more sensitive to noxious substances than I am.....and, of course, I always wash my hands after gardening, and I'm not inclined to lick my fingers or rub my eyes after touching any plants, whether or not I believe they are poisonous. Hopefully these ingrained habits will stand me in good stead now that Coronovirus is the new enemy.

Has that saved me from being poisoned? Hard to say. But it does seem to be good advice generally.

More Poisonous Plants in This Series

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

Questions & Answers

Question: My granddaughter put a couple of hydrangea flowers in her mouth, but she seems fine. What else should I do?

Answer: Clearly, by the time I received this question, you would probably have discovered whether the hydrangea flowers had any ill effects. My advice to anyone else reading this would be to speak to a pharmacist or doctor as quickly as possible. I am not in a position to give detailed medical advice - I studied law, not medicine!

Question: Can iris leaves give you a rash like poison ivy?

Answer: Iris leaves can give you a rash, but it would depend on your sensitivity, I imagine, as I have certainly never had a problem when handling them. I don't know for sure whether it is similar to a poison ivy rash, but I think it is.

Question: I trimmed my hydrangea back and there were numerous dead stalks sticking up. I reached down to clear the old leaves and the stalks ripped my skin in several places. I developed cellulities and a skin rash. Did the dead hydrangea stalks cause this?

Answer: Hydrangeas can cause skin problems on some people. Certainly, if the skin rash and cellulitis occurred exactly where your skin was ripped, then it does seem likely that hydrangea was the cause. As I said in my article, the poisonous parts are leaves, buds, flowers, and bark.The poisonous component is Hydragin.

According to Healthline : "Cellulitis occurs when certain types of bacteria enter through a cut or crack in the skin. Cellulitis is commonly caused by Staphylococcus and Streptococcus bacteria."

I won't go into more detail here, but the upshot is that you should see your doctor as cellulitis can be serious.

Question: I have a hydrangea planted right outside a large window. I've been ill for a while; I've been shaky and have been having difficulty breathing. Could the bush have poisoned in the air?

Answer: This is debatable.

According to Pollen Library (http://www.pollenlibrary.com/Genus/Hydrangea/),

"Some reports associated hydrangea pollen with hayfever, but allergenic potential of this pollen is not well studied."

According to Teleflora, (https://www.teleflora.com/floral-facts/best-worst-... Hydrangeas are not allergenic.

According to Allergic Living (https://www.allergicliving.com/2013/03/14/plants-t... hydrangeas can cause allergies, because they release pollen into the air rather than relying on insect pollination.

So the penny still seems to be up in the air, but as the air just might be contaminated by pollen, I would say it might be better to remove the bush.

However, I think you might also want to consider whether this is the first year you have had a flowering hydrangea outside your window, or whether you have had it there for years and have never been affected by it previously. Having said this, I am not a doctor, but it seems possible to me that maybe an allergy can develop suddenly, even when you had not previously been allergic to the same substance.

If you do reluctantly decide to remove the plant, remember that it's easy to take cuttings of hydrangea and pot them up. When they have rooted, plant one or more of them in a more distant part of the garden where you won't constantly be breathing in any pollen.

Question: I'm growing irises and companion planting with mandarins to see the effect of water retention in the roots, as well as the potential effect on fruiting. What do you think?

Answer: I have never heard of irises being used as companion plants, but it is probably worth a try, just as an experiment.

Feedback - Do Leave your Comment Below - It's so Nice to Know What People Are Thinking

Trisha on June 23, 2020:

Five years ago while gardening including planting a hydrangea I developed a crazy antibiotic/antifungal resistant infection that started on my wrist following a scratch from a hydrangea branch. I recovered after four days in the hospital. We never fully concluded what happened. Was it bacteria on my skin? Was it mulch or potting soil that got into the scratch? This summer while pruning the same plant I scratched my wrist again! Only this time just a tiny bit. It drew no blood just above my glove. I did consider it but without a skin break I continued my hours of gardening. Two days later the rash is beginning again. At first on my wrist, hours later my knuckles, knees, elbows, seems to be rashing at my joints. Five years ago the infection went sesstemic and bloomed at my limpnodes all over my body. Im convinced this was and is an allergy to hydrangea and not a resistance infection. I love hydrangea but I cant touch them. Its poison ivy for me. This is a broomstick hydrangea BTW.

Diana Grant (author) from United Kingdom on September 01, 2018:

Here is a link to the American Society for the Prevention of Cruelty to Animals, stating two long lists of plants which are or which aren't toxic to cats:

https://www.aspca.org/pet-care/animal-poison-contr...

I hope this helps, as they are far more knowledgeable than I am on this subject.

Pat ragano on August 02, 2018:

Are Christmas cactus and Orchids poisenius to cats.

Julie on July 27, 2018:

Hi there.i only have to wlk past Hydrogena and my airways restrict so suddenly i cannot breath and have to get away quickly . This has happened for years now and as my neighbours garden flourishes with them i even have to cross over incase there is any wind. Strange i know but very true

Diana Grant (author) from United Kingdom on June 05, 2018:

Thanks for the information. Poor doggy - I'm glad she didn't suffer lasting effects.

Lori on May 28, 2018:

Hydrangeas are poisonous to dogs....This morning I threw out a flower arrangement and dropped 2 hydrangea flowers...... My 50# standard poodle picked them up and chewed on them, didn't ingest them.... didn't swallow them.....She became seriously nauseated, started throwing up...... couldn't stop ....

I washed her face and mouth with cool water, shaved her front paw(wrist) and applied phenegran gel.....she relaxed and stopped throwing up.... slept a little while...woke and ate some BaKed Chicken...drank a little water..... FEELING BETTER!!... THANK GOD She's OK........!!!!

Katie on May 16, 2018:

I never new the Iris was poison they were just

T sitting there growing in my garden

Thelma Alberts from Germany and Philippines on February 21, 2018:

I didn´t know that these plants are poisonous. Thanks for the heads up.

Diana Grant (author) from United Kingdom on September 21, 2017:

Sorry to hear that. I'm quite surprised, as I've grown masses of crocosmia (montbretia) for years, and have not had any bad experience. No doubt some people are more sensitive than others.

Joan P on September 16, 2017:

I was recently pulling weeds in my garden and was scratched by the leaf of a crocosmia leafy and it burned my skin and it sent shivers down my left arm, I immediately tried was my skin off with cool water, this did nothing, so I tried antibacterial soap, then vinegar which seemed to work the best! After it still burning and tingling (not a nice tingle either)! I then tried aloe straight from the plant! After an hour it is less painful! I do have contact dermatitis but never anything like this!!!

David on October 29, 2016:

I was born and raised in Savannah, GA. My siblings, my friends, and I ate azalea flowers all our childhood. Whenever we were hungry and outdoors, we'd pick azalea flowers and eat them like crazy. They are actually quite sweet and delicious!

Amy on June 20, 2016:

I recently planted four Hydrangeas very close to my vegetables. I have no idea they are poisenous. Does anyone know if it is safe? I really appreciate your help.

Thanks a lot!

Ana Maria Orantes from Miami Florida on August 08, 2015:

I like your hub. Some plants are dangers. It is true. I am glad . you are making people aware of this beautiful poisenous flowers. I treat any flowers with causious because It is not easy to know. What, the plants and flowers can do to us. You did an exvellent job. I like the pictures. The information and orginization is good. Thank you miss gloriousconfusion for the information. Do not forget to check your subtittles.

sandrawelch on August 08, 2015:

Very informative, thank you. I like to walk with my grandson, being four, he likes to touch every thing. Being a very sweet little boy, he always wants to pick flowers to take home to Mommy. I appreciate the list, and plan to use it.

Virginia Allain from Central Florida on August 07, 2015:

I had no idea that the hydrangea was a problem plant.

Since I have no children around, I'll continue to cultivate it.

Kathryn Grace from San Francisco on September 13, 2014:

Thanks for the information. My 2-year-old granddaughter and I encounter hydrangeas frequently on our walks, so I am grateful to learn that all parts of the plant are poisonous. She asks me the name of almost every plant in her field of vision and increasingly shows interest in the different types and sizes of leaves.

About the Egyptians using bits of the iris plant in their tooth care mixture, don't you always wonder how the ancients made these discoveries? I certainly do.

Susan Holland from Southwest Missouri on September 13, 2014:

Interesting! I have the plants, and I never considered them poisonous.

Thanks for sharing! Votes and shared! :-)

Barbara Tremblay Cipak from Toronto, Canada on September 13, 2014:

I'm a little in the dark on what's toxic in the plant department, so I appreciate your page very much!

Sandy Mertens from Frozen Tundra on September 13, 2014:

These flowers are very pretty. Interesting to find that they are poisonous.

Mary Crowther from Havre de Grace on September 13, 2014:

Glad to know this for when my grandchildren come to visit.

Melody Lassalle from California on September 13, 2014:

I can attest to the fact that hydrangea is poisonous. My sister brought one over in a basket. We didn't know it but a leaf fell off. About 15 minutes later my dog threw up. And, then she continued to do so for the next hour and a half. She did rid herself of all the pieces of leaf. And, she was fine a few hours later. It was sure scary though. I remember reading later that although it doesn't produce cyanide, it has cyanide like affects. It's usually not deadly, but boy, it sure gave my dog an upset stomach.

amandascloset0 on May 11, 2014:

I have always kept hydrangea's and poinsettas around my house. I've had other poisonous plants but mostly those two. Because of this I have kept myself aware of what plants are poisonous and what to do if a child were to eat them. The best defense for me is making sure that children know if you put this in your mouth it will make you very sick and could kill you.

GrammieOlivia on May 06, 2014:

Always good to know these kinds of things.

Ramona from Arkansas on April 10, 2014:

Very informative. Thank you. Your lens is lovely.

burntchestnut on December 03, 2013:

We need to continuously teach our children about all plants; what to grow so they can have food, what to forage if they ever need to, and what plants are poisonous (including mushrooms).

blue22d on July 24, 2013:

Oh bum! I love the blue iris - had no idea. Just recently visited The Getty Center in Los Angeles and in their garden they have azaleas - at the center - who would have known. Any cases of people dying from the normal garden usage? Most probably would not eat them - best not to have around little children. THANKS for the info.

Diana Grant (author) from United Kingdom on July 20, 2013:

@anonymous: : Thank you for your message which will be dealt with as soon as possible.

This is an automated reply.

anonymous on July 20, 2013:

I have always liked hydrangea's, they are one of my favourite flowers, but I had no idea they were poisonous! Very informative lens.

liny-tan on May 24, 2013:

this is an information to be kept always in my mind!

Barbara Walton from France on May 16, 2013:

I trained as a Landscape Architect so had to know a little about which plants to use, and which plants to avoid. the poisonous plants came into the latter category, but I didn't know that any of these plants were poisonous.

Rose Jones on May 10, 2013:

This is important information, especially since my dog loves to chew up plants in the garden. Bookmarked so that others see this info.

lionmom100 on May 05, 2013:

I have almost all of the above in my garden. I try to plant some of our Pacific Northwest natives, many of which are not poisonous and have been used as food sources by Native Americans

Diana Grant (author) from United Kingdom on April 24, 2013:

@hemantets: Yes, I have some beautiful artificial silk plants. Thanks for the info

hemantets on April 24, 2013:

Really plants like iris, azalea and hydrangea are very dangerous for all, these are very toxic which is very bad for our body system. Here we can use artificial azalea and hydrangea plants, I think this website (www.qualitysilkplants.com) is helpful to purchase artificial azalea and hydrangea plants.

AgingIntoDisabi on March 30, 2013:

Very ironic that some of the most pretty plants are poisonous. Thanks for letting us know.

marsha32 on March 29, 2013:

Irises are my favorite flowers. I wouldn't have ever known they are poisonous.

Diana Grant (author) from United Kingdom on March 29, 2013:

@Lee Hansen: good one! Or how about Flowers to Die for?

Lee Hansen from Vermont on March 29, 2013:

Gives new meaning to the phrase Drop Dead Beautiful ...

cmadden on January 04, 2013:

News to me!

Diana Grant (author) from United Kingdom on January 02, 2013:

@Michey LM: Yes, it is surprising. The thing is, you can still grow them, but just be careful not to stay in contact with them for long, and be sure to wash your hands before you touch your mouth.

Michey LM on January 01, 2013:

I don't know that iris, azalea and hydrangea can be poisonous - it is a total surprise for me... especially because I like iris and azalea. thanks for shearing!

wecomparebooks on June 28, 2012:

I learned a lot from this lens!

wecomparebooks on June 28, 2012:

I learned a lot from this!

Lori Green from Las Vegas on June 25, 2012:

I didn't kknow Iris was poisonous either. I tried to have a poison free yard when my kids were little. Oh well, at least they never ate them.

anonymous on June 14, 2012:

I am enjoying your website. Did not know that the iris was poisonous. Just started planting them in the last couple of years. I will have to make myself wear gardening gloves now. Thanks for the info.

JohnCumbow on May 28, 2012:

Never realized I had all these toxic plants growing around my country garden. They're all so beautiful. Thanks for the heads-up!

Helene-Malmsio on May 22, 2012:

Well well, I did not know that any of these three plants were poisonous - I really learned something useful today, thanks!

burntchestnut on May 07, 2012:

I know quite a bit about poisonous plants because I love reading old mysteries like Agatha Christie.

kimark421 on March 26, 2012:

Obviously I don't know my poisonous plants, I had no idea Iris and Azalea were on the list. Thank you!

Ladyeaglefeather on March 18, 2012:

Great lens. Thanks for all the information. I didn't know, a lot of these plant were

poisonous.

knit1tat2 on March 12, 2012:

nice and informative lens. Thanks!

anonymous on February 29, 2012:

thanks for the informative lens!

hsschulte on February 10, 2012:

I have many of these growing outside. I will have to warn my kiddos. Thanks.

Jules Corriere from Jonesborough TN on November 19, 2011:

I never knew azaleas were poisonous. I did find out Wisteria is poisonous, after my nephew put a pod in his mouth and started to swell up. Thanks for this lens. It was sooo interesting!

KimGiancaterino on November 05, 2011:

Thanks for this warning. I've never had success growing any of these plants, so maybe it was a blessing in disguise. My cats are forever munching on grasses, and I try to keep toxic plants out of the garden.

Optionstradingiq on November 04, 2011:

Wow, I had no idea Azaleas and Hydrangeas were poisonous plants! Good to know.

sousababy on June 27, 2011:

Wow, good to know. I'm not much of a gardener at all. Thanks for the education.

pheonix76 from WNY on June 27, 2011:

Thanks for this informative lens! I love all three of these plants, but never realized that iris were poisonous. :O I have many iris plants in my flower garden and there are plenty of Azaleas and Hydrangeas around my area. Thanks again for sharing!! (:

Chardoo on May 31, 2011:

Both of these beautiful plants grow everywhere in the Puget Sound, Washington State area. My daughter has had to replant hers to the front yard for a nice street view and keep her three tiny dogs in the back yard where they have safe, edible plants.

Patricia on May 21, 2011:

@Gloriousconfusion: Your welcome!

Diana Grant (author) from United Kingdom on May 20, 2011:

@ZenandChic: Dangerous to eat flowers and leaves, and even the honey sourced from these plants. Thanks so much for the Angel Blessing!

Patricia on May 20, 2011:

Are they dangerous to touch or eat? I just photographed both kinds of these flowers... Irises and Azaleas.

June Campbell from North Vancouver, BC, Canada on March 10, 2011:

I had no idea these three beautiful plants were poisonous. All three grow prolifically in Vancouver. It's good to know.

sukkran trichy from Trichy/Tamil Nadu on February 17, 2011:

thanks for the useful info.

Craftybegonia on February 15, 2011:

That is a great warning to give. It would be horrible if one's pet gets killed by chewing on a toxic plant! They have beautiful flowers though...

Moe Wood from Eastern Ontario on January 26, 2011:

I did not know hydrangeas were toxic. I have a few in the yard I'll have to make sure dog doesn't get into it.

anonymous on December 03, 2010:

Toxic plants: I want to find out as much as I can about these plants. You see, we've got a very large garden/aboretum which would cost at least A$8,000 to fence,and then some native animals can get over/thru. fences. We've found that all our 'resident' native animals either are scared off some toxic plants straight away, or they eat a tiny bit and then stop straight away. That way we can have a great garden and enjoy seeing our animals come out at night to graze only on our lawn. (saves lawnmowing?)Knowing all we can about toxic garden plants ensures we and our animal friends live together. We come from Tasmania, Australia.

ICanCook on November 12, 2010:

I'm a gardener and I'd love anything from this site. I also didn't know Azaleia and Hydranga were poisonous. I have both in my garden. Thanks for the info.

dustytoes on November 06, 2010:

Nope, I sure didn't know that hydrangeas are poisonous, but when I work around Azaleas I always get an itchy rash. I enjoyed your informative lens and will lensroll.

jamesraynor79 on November 03, 2010:

Even though they are deadly, they are still very beautiful. If you are looking for beautiful, but deadly flowers, check out CanadaWideFlowers.com. You can shop flowers to your heart's content.

tssfacts on October 26, 2010:

Great article. I knew that Hydrangea were but didn't know about the other two.

myneverboredhands on October 16, 2010:

Another great and informative lens. Thumbs up!

Diana Grant (author) from United Kingdom on September 21, 2010:

@OhMe: Thank you so much for blessing - that was valuable information too!

Diana Grant (author) from United Kingdom on September 21, 2010:

@Hairdresser007: Well, six months have passed since your stated intention to creat a lens on irises - how have you got on, and did you ever create an Iris Area?

I'm not very good with irises - they seem to get overgrown by other plants, or eaten by slugs and squirrels, so only two flowered this year (but they were gorgeous!)

Nancy Tate Hellams from Pendleton, SC on September 21, 2010:

Thank you for this valuable information on Poisonous Garden Plants. Blessed.

Barbara Radisavljevic from Templeton, CA on March 28, 2010:

Do you think irises are poisonous to gophers as well as to humans? I don't think my gophers have eaten any of mine yet, but I thought it was just luck. I've planted lots of daffodils because they are supposed to be poisonous to gophers. The little rodents seem to enjoy my lantana, though..

James Jordan from Burbank, CA on March 23, 2010:

I love this lens. Great idea. I am trying to create a lens on irises but am waiting for my 1 iris to bloom. I want to create an iris area and there is an iris club not to far from here so hopefully I can get some good info. Thank you for this one!

anonymous on March 20, 2010:

It wouldn't know a toxic flower, just haven't read up on that much at all. This is good information. I'd love to know more about mushrooms that we can eat from the wild. This is good information you have here and interesting. ~ Well done! - You are cool! :)

Susie

bobtyndall on March 19, 2010:

Good information. Are you aware that rhubarb leaves are poisonous also. Although I have never heard of anyone getting sick from them. Also, these poisonous plants lose their toxicity in the compost pile.

Davidfstillwagon on March 13, 2010:

Good lens, the azealeas are about to bloom here in the South.

5*

JewelRiver on March 13, 2010:

This is a great lens 5 stars!