by Stacy Tornio
THE BOTTOM LINE
Stay away from this one if you see it in the wild. Don’t be drawn in by its cute, button-shaped, and curious-looking yellow blooms.
NIGHTSHADE
POISONOUS PROFILE
Many plants go by the name of nightshade, and you pretty much want to stay away from them all. The one pictured here is a vine with the most beautiful deep-purple flowers, but don’t let them fool you. You don’t want any part of it. Also keep an eye out for similar plants with this bloom shape or in this family. While some are more toxic than others, you pretty much want to avoid them.
DEADLY STATS
Common Name Nightshade, bittersweet nightshade, climbing nightshade
Botanical Name Solanum dulcamara
Zone 4 to 8
Height up to 7 feet
Spread up to 7 feet
Flower Color Purple
Light Needs Full sun to part shade
Level of Toxicity 3
Toxic Parts All parts, which can cause irritation to the skin as well
BE AWARE
This is one of the more deadly plants you can find in the garden, and this one can especially be a problem because it grows fast and spreads quickly. If consumed, it can cause vomiting, upset stomach, and even death in serious cases and large quantities.
THE BOTTOM LINE
Find a different vine if you’re looking for something to grow up that trellis.
CASTOR BEAN
POISONOUS PROFILE
This plant first gained popularity because it’s huge and very striking. It can shoot up to 10 feet in a single growing season, and the little seed balls you find on the plant are red and spiky. However, it comes with a price. Those little seeds can really do some damage if consumed by people or pets. The plant can also cause irritation if you touch it or rub against it.
DEADLY STATS
Common Name Castor bean
Botanical Name Ricinus communis
Zone 9 to 11
Height up to 10 feet
Spread up to 4 feet
Flower Color Small greenish-yellow flowers, though mostly known for the spiky red seed capsules
Light Needs Full sun
Level of Toxicity 3
Toxic Parts All, but the seeds are most dangerous
BE AWARE
Nausea, vomiting, abdominal pain, respiratory problems, and even death can occur if consumed. Also, symptoms don’t always show up right away.
THE BOTTOM LINE
It’s aggressive, it’s highly poisonous, and it’s not worth it. Don’t encourage it in your garden.
WISTERIA
POISONOUS PROFILE
Wisteria is one of the coveted plants that once you see it growing, you really want to have it yourself. It might take a couple years to get wisteria established, but once you do, it’s so beautiful. It produces gorgeous spring blooms, year after year. This vine can get pretty huge, so keep this in mind if you plant it. You’ll want to either grow it on a support system or have it in a place where you can add support once it’s established.
DEADLY STATS
Common Name Wisteria
Botanical Name Wisteria frutescens
Zone 5 to 9
Height up to 30 feet
Spread up to 8 feet
Flower Color Lilac or purple
Light Needs Full sun
Level of Toxicity 1
Toxic Parts All parts, especially the seeds and seed pods
BE AWARE
If your pet eats parts of this plant, you might notice signs of vomiting, diarrhea, and upset stomach. It can even cause pet depression!
THE BOTTOM LINE
This one is probably fine to grow in your garden. It often grows as a vine, so your pets might not even be able to reach it.
MOONSEED
POISONOUS PROFILE
This plant is a common vine across North America. While it’s not one often grown in backyards, you will see it in the wild. In fact, it can look a lot like wild grapes, which is why it’s so important to know what you’re looking for if you go foraging. This plant spreads by rhizomes, so if it does get going in backyard gardens, it can be a bit aggressive.
DEADLY STATS
Common Name Moonseed
Botanical Name Menispermum canadense
Zone 5 to 8
Height up to 20 feet
Spread up to 6 feet
Flower Color Greenfish-white flowers
Light Needs Full sun to part shade
Level of Toxicity 3
Toxic Parts All parts, especially leaves and fruit
BE AWARE
The fruit on this plant looks a lot like grapes, and it can be fatal.
THE BOTTOM LINE
Do not confuse this plant with wild grapes. It can be tricky, but be sure you know what you’re looking at.
POISON PARSNIP
POISONOUS PROFILE
Poison or wild parsnip is a bit of a sneaky plant. It looks a lot like a wildflower. However, if you come into contact with it, it could cause a serious burning and blistering of your skin within a short amount of time. This plant, considered a weed by many gardeners, is common in pastures, along roadsides, and other parts of the wild. It’s important to know what it looks like and not confuse it with other look-alikes.
DEADLY STATS
Common Name Poison parsnip, wild parsnip
Botanical Name Pastinaca sativa
Zone 4 to 9
Height up to 5 feet
Spread up to 3 feet
Flower Color Yellow
Light Needs Full sun
Level of Toxicity 1
Toxic Parts All parts
BE AWARE
It might not cause death, but it contains a substance that makes skin sensitive to light. If you handle this plant, it could cause mild to moderate skin irritations, which look a lot like burns or blisters.
THE BOTTOM LINE
Don’t handle it at all. It’s pretty weedy, so it’s not a desirable plant overall.
CLEMATIS
POISONOUS PROFILE
Clematis is one of the most popular vines in the garden. There are many different types of clematis out there, and the beautiful flowers that this plant is known for come in many different shades. Clematis starts off small in the spring, but it doesn’t take long for it to grow up a trellis or pergola. As a bonus, many gardeners are able to grow it in partial shade, making it a truly versatile bloom.
DEADLY STATS
Common Name Clematis
Botanical Name Clematis
Zone 5 to 9
Height up to 10 feet
Spread up to 6 feet
Flower Color Blue, white, purple, pink, red
Light Needs Full sun to part shade
Level of Toxicity 1
Toxic Parts All parts
BE AWARE
Clematis can cause mouth pain to animals who eat it. Other side effects include vomiting, salivating, and diarrhea.
THE BOTTOM LINE
It’s probably fine for most backyards and gardens, but keep it away from pets.
BRYONIA
POISONOUS PROFILE
Bryonia definitely falls into the weed category. While it’s not native to the United States, a type of bryonia (white bryony) can be found in western parts of the United States like Washington, Montana, and Idaho. It’s never a good idea to eat unknown berries in the wild, but you should definitely keep a watch out for this vining plant.
DEADLY STATS
Common Name Bryonia, bryony
Botanical Name Bryonia
Zone Mostly native to parts of Europe and Southeast Asia
Height 20 feet or more
Spread 10 feet or more
Flower Color A greenish-white flower
Light Needs Full sun
Level of Toxicity 3
Toxic Parts All parts, especially the berries
BE AWARE
If you consume any parts of this plant or the berries, you may experience naus
ea or vomiting. As little as 30 to 40 berries could cause death in humans or animals.
THE BOTTOM LINE
Skip it!
MISTLETOE
POISONOUS PROFILE
Many people don’t know this, but mistletoe is actually a type of parasite. Seems weird, right? Isn’t this just a holiday plant that encourages people to kiss? This is a plant that lives on trees, and it actually can do a lot of damage to the trees if left untreated. Mistletoe attaches to trees, and then it sucks away vital water and nutrients. If you don’t do something to get rid of it, it can actually kill the tree.
DEADLY STATS
Common Name Mistletoe
Botanical Name Phoradendron serotinum and Viscum album
Zone 3 to 9
Height Up to 5 feet
Spread Up to 5 feet
Foliage Green with small white berries
Light Needs Sun to part shade
Level of Toxicity 1
Toxic Parts All parts, but especially the berries
BE AWARE
For humans, it’s mostly the berries from mistletoe that you have to worry about. If you or even a pet consumes them, you could see side effects like vomiting and an upset stomach.
THE BOTTOM LINE
If you notice a tree with mistletoe in it (it’s usually really high up), try to get help from an arborist. Remove the mistletoe, if possible.
TRUMPET VINE
POISONOUS PROFILE
Trumpet vine is one of the biggest, most striking, awesome hummingbird plants that you can grow. Once you get it established, it loyally comes back every year, growing 20, 30, and even 40 feet, attracting hummingbirds the entire season. The trumpet-shaped flowers are gorgeous and bright. They will also attract butterflies and bees. You definitely need a strong support system to grow this vine—an old stump, a sturdy pergola, even a telephone pole. It’s truly one of the most eye-catching plants in the garden.
DEADLY STATS
Common Name Trumpet vine, trumpet creeper
Botanical Name Campsis radicans
Zone 4 to 9
Height 10 to 40 feet
Spread 5 to 20 feet
Flower Color Orange, scarlet, or yellow
Light Needs Full sun to part shade
Level of Toxicity 1
Toxic Parts Leaves, flowers
BE AWARE
If you touch this plant, it could cause some minor skin irritation like redness. If consumed, mild effects include vomiting and nausea.
THE BOTTOM LINE
The toxic elements are pretty low, so this is one that you should feel okay about planting.
WATER HEMLOCK
POISONOUS PROFILE
You might know the name hemlock because of the tree, but this is in a completely different botanical family. You usually find it growing in the wild. It’s especially common in wetland areas and around pastures and streams. It’s one of the most deadly plants you can find in the wild, both to animals and humans. Some people often mistake it for parsnips or herbs, but if you see something like this plant growing, just let it be!
DEADLY STATS
Common Name Water hemlock
Botanical Name Cicuta douglasii
Zone 5 to 9
Height up to 3 feet
Spread up to 3 feet
Flower Color Small white clusters of flowers
Light Needs Part sun to part shade
Level of Toxicity 3
Toxic Parts All parts, especially the roots
BE AWARE
If consumed, especially the roots, this can cause serious seizures and convulsions. It can also lead to heart issues and even death.
THE BOTTOM LINE
If you come across this, leave it alone!
MONKSHOOD
POISONOUS PROFILE
This plant also goes by the common name of wolfsbane because parts of this plant were once used to poison wolves—both as a bait and also as a poison in the arrow. It has a long history of growing in the wild and being used for poisonous purposes, so you definitely don’t want to consume it. However, it’s still popular among gardeners, especially for its bluish blooms. They make a statement in the backyard!
DEADLY STATS
Common Name Monkshood, wolfsbane
Botanical Name Aconitum napellus
Zone 3 to 7
Height up to 4 feet
Spread up to 2 feet
Flower Color Purplish blue flowers
Light Needs Full sun to part shade
Level of Toxicity 3
Toxic Parts All parts, but especially the roots and leaves
BE AWARE
If consumed, you’ll see nausea and vomiting, along with burning, tingling, and numbness. You or your pet might also see difficulty breathing, dizziness, and serious heart problems, which can lead to death.
THE BOTTOM LINE
Don’t plant it. It’s been known to kill humans, too, and it’s certainly not worth the risk.
PERENNIALS
“If you drink much from a bottle marked ‘poison,’ it is certain to disagree with you sooner or later.”
—Lewis Carroll
68. Milkweed
69. Lantana
70. Tobacco
71. Bleeding heart
72. Snakeroot
73. Larkspur
74. Foxglove
75. Jack-in-the-pulpit
76. Flowering tobacco
77. Buttercup
78. Angel’s trumpet
79. Daylily
80. Hosta
81. Opium poppy
82. Solomon’s seal
83. Chinese lantern
84. Lupine
85. Agave
86. Baby’s breath
87. Flax
88. Yucca
89. Cardinal flower
90. Lily-of-the-valley
91. Four o’clocks
MILKWEED
POISONOUS PROFILE
Milkweed is a good poisonous plant. Yes, really! Here’s the thing—milkweed is the host plant for monarchs. What does this mean and why should you care? It means that monarch caterpillars need this plant in order to survive, and this is important since the monarch population has been plummeting! As gardeners, we can help by planting milkweed in our gardens. So even though the milky sap that runs through this plant’s leaves can make you (and your pets) quite ill if you consume it, it’s still a good perennial to have in your backyard.
DEADLY STATS
Common Name Milkweed, common milkweed
Botanical Name Asclepias syriaca
Zone 3 to 9
Height 2 to 5 feet
Spread up to 1 foot
Flower Color Pink, white
Light Needs Full sun
Level of Toxicity 2
Toxic Parts All parts of the plant because of the milky sap that runs through it
BE AWARE
If you or pets eat it, you might experience vomiting and nausea. If you cut a stem or leaf, this plant will give off a milky substance. Don’t worry—it’s not toxic to touch, but be sure to wash your hands after you handle it. And don’t chomp on it.
DID YOU KNOW?
Why don’t monarch caterpillars die from consuming milkweed leaves? They are pretty much immune to it, which makes for a great defense mechanism. Over the years, animals have learned to not eat monarchs and their caterpillars. Isn’t nature both fascinating and cool?
THE BOTTOM LINE
Despite it being a bit irritable, you should still grow milkweed. The benefits to the monarch population far outweigh the risks.
LANTANA
POISONOUS PROFILE
Lantana is native to the Caribbean. Most gardeners grow it as an annual, but you might find it year-round in warm areas of California or Florida. This is a bloom that is like fine wine: it gets better with time. The small clusters of flowers usually start out as a soft, single color. Then, as the plant ages, they change color and deepen. Grow it in a sunny spot, and you’ll love watching it thr
ive as some of your other blooms fade in the heat of the summer.
DEADLY STATS
Common Name Lantana, red sage, wild sage, yellow sage
Botanical Name Lantana camara
Zone 10 to 11
Height up to 4 feet
Spread up to 3 feet
Flower Color Red, orange, yellow, purple, white, pink, bicolor
