16 Of The Most Poisonous Garden Plants

Most Poisonous Garden Plants

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When we are making gardens, most of us are only concerned with what the plants look like or the way they will taste. However, some of the most popular garden plants can also be potentially dangerous. 

Knowing what these poisonous plants are will allow you to take some extra precautions, like putting them in a place that children and pets won’t be able to access. Keep reading to learn more about some of the most potentially dangerous plants you might find in your garden. 


These are some of the most popular types of plants found in gardens around the world. They have become known for their vibrant ball-shaped flowers. Interestingly, the color of these blooms will depend on the pH levels in the soil. 

However, these plants are hiding a darker side. They contain low levels of cyanideOpens in a new tab.. This is one of the most dangerous substances available. If you take enough, you could die. 

The good news is that the amount present in a hydrangea is unlikely to be fatal. But it can make you sick. Here are some of the symptoms that you should be looking for:

  • Vomiting
  • Breathing heavily 
  • Stomach pains
  • Lack of energy
  • Mental health symptoms, like depression. 

There are a few reasons why these problems might start to manifest. Most commonly, you will need to eat the plants. To get sick, you will need to eat a large amount of these plants. Because of this, this type of poisoning is fairly rare. 

However, there is also a chance that you will start to experience issues just by handling the plant. However, these tend to be mild. You might just get a skin rash. If you are experiencing this, it’s a good idea to wear gloves when you are working with these plants. 


This is a stunning flower, which is known for its pink blooms. It’s particularly popular in the Mediterranean region. They are also found in some parts of Asia. Not only is it beautiful, but it’s also easy to grow. You don’t need to put in a lot of effort to maintain its beauty. However, it has a powerful toxin in them, known as cardiac glycosides. 

There are many examples of how powerful these toxins can be. For example, one leaf was enough to cause serious issues with a child. This tiny dose has been enough to kill dogs. In large animals, like a horse, it takes just 0.005% of their body weightOpens in a new tab. to prove fatal. 

It should be noted that you can get sick without ingesting the leaves of the plant. Fires have been known to make the toxin airborne. Breathing in the smoke will make you sick. Though, it’s unlikely that you are going to die from this level of exposure. 

There are a few signs that you might have been exposed to the toxin, including: 

  • Severe digestive problems
  • Vomiting
  • Skin irritation, if you touch the leaves

If you have been exposed, you will need to take action as soon as possible. Using activated charcoal, you might be able to reverse the damage associated with this toxin. 


These are some of the most popular decorative plants. Their golden flowers have proven to be a popular accessory in gardens around the world. Plus, they are easy to grow. They are resistant to the cold temperatures that can strike in the late fall. 

However, there is another side to this ornamental flower. It releases a toxin into the air. Unlike some of the other plants on the list, it won’t be enough to kill you. But it will be enough to make you feel sick. 

Most commonly, this will happen when you are keeping the daffodils in a room that doesn’t have good ventilation. This allows the toxin to build up in the air. It can leave some people feeling lightheaded. Some of the other symptoms include: 

  • Headaches
  • Feeling sick
  • Vomiting
  • Heartbeat irregularities. This is most commonly seen in pets
  • Tremors
  • Dehydration
  • Drooling

The good news is that there are some easy ways that you can solve this problem. You can put them outside. This will allow the toxin to diffuse with the air. This should eliminate most of the problems. However, it’s still a good idea to take some measures to stop your plants from eating them. 


These are beautiful tubular flowers that grow on long stems. This allows them to create a cascading effect, which looks great in your garden. They come in a range of temperatures. Most commonly, they are pink. However, you can also find them in yellow, pink, and red. Plus, they are resistant to extreme temperatures. 

Interestingly, this toxin has been used for good. It is an important ingredient in some heart medications. However, in the wrong hands, it can prove to be very dangerous. Just touching the flowers, then touching your face, is enough to transfer the toxinOpens in a new tab.

Things can get even worse if you ingest the flowers. It doesn’t take much to create a lethal dose. Just a handful of flowers will be enough to kill you. Because of this, you should keep these plants well away from dogs and children. 

Some of the most common symptoms that you have been exposed to the toxin in the Foxglove are: 

  • Skin irritation
  • Fatigue
  • Blurred vision
  • Changes to your color perception
  • Diarrhea
  • Loss of appetite 

Poison Ivy

This is one of the most well-known poison plants. It’s a vine that is known for growing up the sides of buildings. If you have a lattice, you will be able to cultivate this type of plant fairly easily. Sometimes, it can grow up to 100 feet tall. 

Despite its name, it’s one of the least dangerous plants on this list. Most commonly, when you touch this plant, you will develop a rash. You’ll also feel some pain in your skin. This might manifest as an itch. This should fade after a while. 

Thankfully, you don’t need to worry about how your pets will respond to this plant. They have thick fur. This will provide a level of protection, so the poison won’t be able to reach their skin. 


Interestingly, this is a relatively common vegetable. There are plenty of ways that you will be able to use it in the kitchen. But you need to be careful about the part of the Rhubarb that you are eating. You will only be able to eat the stems. If you try to eat the leaves, you can run into some problems. This part of the plant is toxic. 

There are a few problems that you might face if you eat itOpens in a new tab., including: 

  • Burning in your mouth or throat
  • Breathing problems
  • Eye pain
  • Weakness
  • Red urine

Over time, these problems can become even worse. In some cases, it might be able to cause kidney damage. It might even be enough to put you into a coma. 


Wisteria trees can be a beautiful sight. Their vine-like flowers are a great way of decorating walkways, as the pink stems hang down and sway in the breeze. But, under some circumstances, they can prove to be toxic. 

Humans might be affected if you decide to chew the flowers or leaves. Some of the symptomsOpens in a new tab. to look out for include: 

  • Burning in your mouth or throat
  • Nausea
  • Difficulty swallowing
  • Vomiting

While unpleasant, these problems will only last for a limited period. In most cases, they will only last for a few hours. After this period, you should be OK. However, things won’t work out as well for your pets. They shouldn’t eat the seeds. 

If they have been affected, you should look for vomitingOpens in a new tab.. Sometimes, they will be throwing up blood. They might also change their mood. There are some times when your pets might become depressed after eating these seeds. 

Lily of the Valley

These plants have proved to be popular because of their beautiful white bell-shaped flowers. They are commonly found in Asia and Europe, thriving in the colder regions. Despite their beauty, though, these flowers can prove to be very dangerous. 

It contains 38 different types of cardenolides. These have been used for medicinal purposes. However, if you eat them raw, they can release a lot of poison into your bloodstream. This can prove to be a fatal mistake. All the parts of this flower will prove to be toxic. 

There are a few common side effects that come from eating this plant. Some of the most common issues you can face include: 

  • Tremors
  • Seizures
  • Vomiting
  • Irregular heartbeat
  • Changes to your mental state. You might start to become confused

These issues will get worse if your dog or cat ingests the Lily of the Valley. Shortly after, you will notice a pronounced change in their behaviorOpens in a new tab.. For example, it’s common for them to start drooling. You might see the way they walk starts to change, starting to stagger as though drunk. They might even become weak and collapse. If you notice any of these problems, you will need to take them to the vet as soon as possible. 

Easter Lilies

These are some of the most popular types of flowers, especially around Easter, when their beautiful white blooms start to open. However, all parts of this plant are toxic. If you eat them, you will start to experience the effects fairly quickly. In most cases, you will start to get dizzy, and you might start to have stomach painOpens in a new tab.

The most common problems occur when your cats eat the lilies. The toxins in the lilies will cause kidney damage. It might also start to cause heart irregularities. It won’t take a large amount to cause deathOpens in a new tab.. If your cat has been affected, you will need to bring them to the vet as soon as possible. Without treatment, they will die. 

Elephant Ear

These plants are known for their wide, green leaves. They are a common plant to grow inside the house. However, these are extremely toxic. Even brushing against these leaves can cause problems. They can cause skin irritation. If you then brush it against your face, it can cause a burning sensation in your mouth.  


Mistletoe is one of the most popular decorations around the Christmas period. Millions of people share a kiss under its leaves and small white berries. But this plant contains a relatively large toxin load. All parts of the Mistletoe are poisonous. Though there are plenty of types of Mistletoe, they are all potentially dangerous. Some have more potent toxins than others. 

There are a few common effects of Mistletoe poisonOpens in a new tab.:

  • Blurred vision
  • Fever
  • Slower heart rate
  • Stomach pain
  • It has been linked to birth problems 
  • Gastroenteritis


If you are looking for a way to add a little extra color to your garden, you might want to consider using the Larkspur. It is known for its beautiful flowers, either white or purple. They are popular because of how easy it is to maintain them. 

However, Larkspur has a relatively high concentration of alkaloids. The seeds have the highest concentrations of toxins. When ingested, they can cause potentially significant problems. One of the most common issues is a burning sensation in the mouth and some vomiting. But the biggest concern is that your heart rate will start to lower. At present, there is no proven treatmentOpens in a new tab.


These are easy to grow, especially in a warmer climate. Because of this, it’s common to find them in warmer US states, like California. Because of their bright leaves, these are often used as part of the festive season. It’s common to turn the leaves into decorations around the house. 

The good news is that this is one of the least dangerous plants on this list. You can only run into problems if you ingest the sap. Even if you do, you’ll need to consume a large amount of the toxin to be killed. 

Purple Nightshade

These plants have started to fade out of gardens as people realize how dangerous they are. But some people like to keep them around because of their beautiful flowers, which shine in the sun. They are often found around West Asia and Europe.

While it might look pretty, the nightshade is one of the most toxic flowers you can grow. Every part of it will be toxic, though the berries are the most dangerous part. You won’t need a large dose to start to experience the detrimental effects; just a handful of berries will be enough to cause damage. Some of the potential problems include: 

  • Losing your voice
  • Convulsions
  • Digestive problems

The Nightshade toxin will be powerful enough to kill humans if you consume enough.  

Desert Rose

This is a beautiful flower, with pink blooms. These require a dry environment to cultivate. Because of their small size, with most only growing a few inches a year. Because of this, they are often compared to the bonsai plant. 

Despite their small stature, the poison contained in the sap can be very dangerous. To humans, it’s unlikely to do a lot of damage. The body will be fairly good at removing the toxin from your system. 

But to animals, it can be more deadly. Some African tribes used to dip the tip of the arrow in the sap. This would be potent enough to bring down an elephant. If your pet licks this plant, they can become very sick. You might notice diarrhea or vomiting. Sometimes, you will see mood swings as they enter a depressive stateOpens in a new tab.

Angel Trumpets

Part of the reason why the Angel Trumpet got its name is because of the beautiful blooms. These look like yellow umbrellas hanging from the tree. However, this type of plant can be very dangerous. They come from the nightshade family, which are known for their strong toxins. This variety is one of the most toxic forms of garden shrubs in the world. 

All parts of this plant are poisonous. However, the flowers will contain the highest toxin concentrations. There are a few symptomsOpens in a new tab. that can indicate that you have been exposed to the toxin, including: 

  • Muscle weakness
  • Dry mouth
  • Rapid pulse
  • Fever
  • Convulsions
  • Hallucinations. This aspect can sometimes be exploited, turning it into a powerful drug that is sold on the black market. 

If you experience any of these problems, you should talk to a medical professional as soon as possible. It won’t take a lot of the toxin to provide a fatal dose. 

Are Angel Trumpets Illegal?

Buying the drugs produced by the Angel Trumpet toxin is illegal. However, whether growing them is illegal will depend on where you live. Maitland in Florida banned the planting of new Angel Trumpet flowers in 1995Opens in a new tab.. Previously established plants could still be kept. 

Some other states, like LouisianaOpens in a new tab., stop you from growing the plants for human consumption. However, you can still grow them as ornamental flowers for your garden. Because of this, it’s best to check the laws in your local area before you plant these. 

Final Thoughts

There are many poisonous plants that you might find in your garden. Just because they are high in toxins doesn’t mean that you have to pull them out. But you will need to make sure that they are put in an area where children or dogs won’t access them. 

Check out: Composting Cherry Pits


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