Poison Gardens

Happy October, House Plant Hobbyists! We love this time of year, so we’re going to spend the month exploring all things dark, spooky, and macabre. What better time of the year to talk about some of the most deadly decorative plants that a person could grow? Some of these are absolutely gorgeous; you’d never think they could be quite so dangerous! Others are plants that you may commonly see and simply not know just how poisonous they really are….

Before we begin: It should be noted that if you are brave enough to grow these, it’s best to keep them away from anywhere people, especially children, or pets may have access to. Also, we advise you to wear gloves when handling any of the following plants, and to never ingest, or give to anyone else to ingest, any part of these plants, even if parts of them have been used medicinally in the past.


Two types of Hemlock plants are known to be extremely poisonous:

Poison Hemlock, or Conium maculatum, is a fairly well known plant in the carrot family that has segmented lacy leaves and clusters of dainty white flowers. Although these have historically been used as medicine, they are most famously known as the poison that felled Socrates. These are not native to North America, but were brought from Europe and Africa to be used as ornamental plants. It should be noted that these are in same family as carrots, dill, fennel, parsnips, angelica, wild parsnip wild cervil, wild celery, cow parsnip, Queen Anne’s lace (Apiaceae), etc., with which they have been known to be confused.

The toxin in the Poison Hemlock is called coniine.

Photo credit: BioDivLibrary on VisualHunt / CC BY

Water Hemlock, or Cicuta maculata (covers most of North America) and Cicuta douglasii (covers the Western part of North America), is the most poisonous plant that is native to North America. These are also in the Apiaceae family, so they also resemble the rest of the plants in the family with their umbrella of small delicate white flowers. It has been noted that historically some Native American tribes have used this to tip their arrows with.

The toxin in the Water Hemlock plants is called cicutoxin.

Deadly Nightshade

Atropa belladonna is also known as Belladonna and is one of the most deadly plants native to Europe. Although they look harmless with their pretty bell-shaped purple toned flowers and sweet black berries that look like over ripe cherries, all parts of the plant are incredibly poisonous. In fact, as few as two berries could kill a child, eating only one leaf can kill an adult, and the roots are even more poisonous, so these are definitely not a plant that you want if you have it in areas accessible to children. The name, Atropa, comes from the name of one of the three Fates of Greek myth, Atropos, who is said to hold your life in her hands and holds the shears that cuts the thread of life’s tapestry. Belladonna comes from Italian words meaning “beautiful woman.” Deadly Nightshade is in the Solanaceae family, as are such veggies as white potatoes, bell peppers, tomatoes, eggplant, cayenne peppers, chili peppers. This means that you regularly eat veggies and spices that are called “nightshade vegetables.”

The toxins in Deadly Nightshade are atropine and solanine.

Castor Bean

Ricinus communis is a semi-woody large shrub to small tree that is in the spurge family and native to East Africa. These have large somewhat tropical looking leaves that come in such colors as glossy green, green with white veins, maroon, bronze green, dark purple, blue-green, blood red, or metallic dark red. The inflorescences, flowers, are equally as unique as they grow 8-18” tall, have cream colored flowers, and with bright red pompom-like flowers. The “beans,” which are actually seeds, are just are showy as the rest of the plant with mottled/striped shades of maroon, white, yellow, brown, black, and grey. These are where the real danger lies, as the toxin in the seeds is one of the deadliest naturally occurring poisons in the world. Ironically castor bean oil is used in various well known items, such as the purgative/laxative castor oil, industrial crop oils, cosmetics, lubrication, and motor oil. The plant got its name from the Latin word for tick, ricinus, due to the seeds resembling a certain type of European tick.

The toxin in the Castor Bean is ricin.

Rosary Pea


Abrus precatorius is a Native to India and parts of Asia, but has been used in the United States, namely Florida, as an ornamental plant. It is a climbing or trailing vine with branches that have pinnated leaves and dense clusters of gorgeous small violet, pink, or white flowers. The long, flat seed pods open up to reveal three to eight shiny, hard, uniformly sized bright red seeds with a black spot. The seeds are so similarly sized that they have been used as a standard in weight measurement. Obviously, going by the name, the seeds are also frequently used to make rosaries and jewelry. This is also the poisonous part of the plant, as consuming a single seed will kill a person. Interestingly birds are not affected at all by the seeds and can eat/carry them in their beaks without any affect. It should be noted that this is on Florida’s list of noxious weeds, so keep in mind that these spread easily and are hard to kill.

The toxin in the Rosary Bead is abrin.



Nerium oleander is an extremely popular ornamental large shrub or small tree that is native to parts of Europe and Asia. The leaves are long, narrow, and deep green, while the gorgeous funnel-shaped flowers come in shades of pink, yellow, red, or white are can have a pleasant fragrance. These are commonly seen all over the subtropical/tropical portions of the U.S., as far north as Virginia, and growing in median strips along roadways in California and Texas. Wherever you go in those states you will see Oleanders everywhere, which is to be expected really, as they’re beautiful plants. The problem is that every part of the plant, whether it is fresh or dried, is poisonous. Just make sure if you own an Oleander and have children that you rake up the leaves, sticks, and flowers, or have them in places that are not accessible.

The toxins in the Oleander are glycosides, digitoxigenin, saponins, nerioside, oleondrin, oleondroside, and possibly other unknown toxins.


Nicotiana tabacum is definitely the most well known plant on this list. Yes, everyone knows about the carcinogens that are present in tobacco leaves, even if the leaves are grown organically and never see a factory. That isn’t what we are talking about, nor are we here to judge those who smoke. Some people know that these actually make quite stunning garden plants with their fairly large leaves and rather pretty flowers. Also, the leaves/oil can be used as a natural pesticide. What a lot of people don’t realize is that there is something called Green Tobacco Sickness, or GTS, which is when a person gets nicotine poisoning from harvesting leaves. Granted, it usually happens when the leaves are covered with dew or water, or the person’s skin is sweaty, but it is a common problem that affects those who pick the leaves. Nictotine isn’t just something that needs to be ingested, as it can enter your blood stream by just touching your skin. This is dangerous for everyone who comes in contact with the plant, but even more dangerous for children. That said, you have to come in contact with quite a lot of these plants, and some nice gloves can keep your exposure to either nonexistent or fairly low levels.

The toxin in the Tobacco plant is nicotine.

Devil’s Helmet

Photo credit: BioDivLibrary on VisualHunt / CC BY

Aconitum napellus has many names, and all of them are a bit… foreboding. Devil’s helmet, monkshood, wolfsbane, leopard’s bane, queen of poisons, etc. These are commonly found being grown in gardens, and if you’ve seen one you know why! They have light to dark green palmate, hand shaped, leaves with clusters of purple/blue, white, or yellow flowers on a tall stalk. They got their most commonly used name, monkshood, due to the fact that the flowers are shaped similar to the that of a medieval monk’s hood. They are quite gorgeous, and to add to their appeal they can tolerate being grown in some lighter shade and almost every zone during the warm months. Of course, monkshood wouldn’t be on this list if it didn’t contain poison. Every single part of these beauties are known to contain poison, so it is best to use caution while gardening. If you’re going to grow them make sure to wear gloves, don’t touch any mucous membranes, don’t let the sap get on your skin, and wash your hands after you are finished handling them. That said, they are absolutely gorgeous background plants that look amazing in any garden, especially if your garden is not accessible to children or curious pets.

The toxin in the Devil’s Helmet is aconite.


Digitalis purpurea has possibly the cutest common name on this list. Foxglove, how could you not think that’s an adorable image? Apparently the flowers reminded people of the fingers of a glove, so they started to call them “foxes glofa,” or the glove of the fox. Also, the “Digitalis” in the botanical name translates to finger-like, which is in reference to the shape of the flower. These are very commonly seen growing in gardens and is often used in floral arrangements. The flower stalks may reach as tall as 6 feet, or 1.8 meters, tall with clusters of gorgeous bell shaped flowers in shades in white, lavender, pink, red, purple, and yellow. Generally the inside of these flowers are speckled with darker and lighter shades, which just makes them even more attention grabbing. You may have noticed the botanical name is the also the name of a heart medication. All parts of the foxglove are poisonous, and ingesting or coming in contact with the plant can cause heart problems and even death. So if you have these, make sure to garden with gloves on, wash any part of your body that has come in contact with them, and as always, keep them away from children and curious pets.

The toxin in Foxglove is digitalis.

Angel’s Trumpet

The name Angel’s Trumpet is a good way to show how common names can be problematic, as there are two closely related plants on this list that have this name.

Photo credit: BioDivLibrary on Visualhunt / CC BY

Datura spp is a genus of nine flowering plants, all of which are poisonous. These are very commonly seen growing in the wild and as ornamental plants, as their white to purple trumpet-shaped flowers are extremely showy and beautiful and spiny fruit. Datura have many nicknames, some of which are very telling — jimsonweed, thornapple, moonflower, hell’s bells, devil’s snare, and devil’s trumpets. All parts of these are poisonous, so make sure to handle with gloves, wash your hands, and never ingest any parts. Keep away from where children and curious pets can access them. These have been used a drug, both pharmaceutical and recreational, but the strength of the toxicity depends on the age, growing conditions, etc, which has lead to many poisonings and deaths. Never consume any parts of a Datura.

The toxins in Datura are atropine, scopolamine, and hyoscyamine.

Brugmansia spp is a genus of seven flowering large shrubs to small trees, all of which are poisonous. Like Datura, these have stunning trumpet-shaped flowers and unlike Datura, the fruit of these aren’t spiny. The flowers come in various colors, which is why these are sometimes even kept as houseplants. Keep in mind that while all parts of Brugmansia are poisonous, the seeds and flowers contain the most toxins. Make sure to wear gloves while gardening, wash your hands after, don’t let the sap get on your skin, and definitely keep these away from children and curious pets. It should also be noted that these used to be classified as Datura, hence the old name, Datura arborea instead of Brugmansia arborea, on the botanical plate.

The toxins in Brugmansia are scopolamine, hyoscyamine, and norhyoscine.

European Yew

Taxus baccata is an often seen evergreen shrub or tree that has iconic bright red berries with openings at the bottom that shows off the seed inside. These trees can live for thousands of years and have quite interesting folklore and mythology. The word “taxus” comes from the Greek taxon for ‘bow,’ which refers to the fact that the wood of Yews have traditionally been used to make bows. I remember being fascinated with these berries when I was a child, and using sticks to remove the seeds. Thankfully I was lucky, because I knew that they were poisonous, but I got which part of the plant was poisonous wrong. It isn’t the brightly colored plump, red arils (berries), in fact, it is every other part including the seed. The toxins within the Yew are present even if the foliage/wood is old a dry, and ingesting as few as three seeds could kill a person. These truly are incredibly poisonous plants, so it is best to not have them where children or pets and farm animals can access them.

The toxins in the European Yew are taxine alkaloids.

Keep an eye out for more spooky posts throughout the month of October here at HPH! If you’re looking for a place to ask questions, share advice, or just show off your plants check out HPH on Facebook to join our global community of plant people.