30 Of The Most Poisonous Plants You Can Find In Your Backyard

1. Poison Ivy

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Poison ivy can be particularly nasty when it is touched by humans.  It generally causes an unpleasant itchy red rash on the skin when it comes into contact with the poisonous and hazardous plant.  And even the smoke from burning it can irritate or harm your nasal passages or lungs.

2. Poison Oak

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Poison oak releases an oil called urushiol when it is damaged and this means that if you touch the plant, your skin absorbs this oil.  Most of the adult population in the US is sensitive to urushiol and this can cause an uncomfortable allergic reaction with a nasty rash.

3. Poison Sumac

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Just like poison ivy and poison oak, poison sumac also releases the oil known as urushiol.  And if this comes into contact with the skin, it can cause a nasty itchy rash.  You may also experience redness, swelling, a burning sensation, and really unpleasant watery blisters.

4. Jimsonweed

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If Jimsonweed is ingested, it can poison you pretty quickly.  In fact, symptoms of Jimsonweed poisoning appear within 30 to 60 minutes and include dry mucus membranes, thirst, fever, blurred vision, an altered mental state,  hallucinations, coma, and in some rare cases even death.

5. Deadly Nightshade

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The berries on Deadly Nightshade look good enough to eat, but if they're ingested, poisoning can be deadly.  Shortly after ingesting them, a person will experience gruesome symptoms, including blurred vision, a rash, headaches, and slurred speech and it can eventually kill a person.

6. Foxglove

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Foxgloves are very poisonous to humans and can prove fatal if they are ingested.  Symptoms of Foxglove poisoning include a stomach upset, muscle weakness and tremors, frequent urination, a strong slow pulse, abnormal heartbeats, confusion, and eventually death.

7. Water Hemlock

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Water Hemlock is poisonous all year round but it is said to be particularly poisonous during Spring.  Poisonings to humans usually happen if the plant is ingested but it also contains cicutoxin which can also be absorbed through the skin in rare cases.  If a human is poisoned by Water Hemlock, they would experience drooling, nausea, stomach pain, and uncontrollable bowel movements in as little as 15 minutes.

8. Angel's Trumpet

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Angel's Trumpet can be fatal to humans.  In fact, poisoning can cause a range of unbearable symptoms if a human touches it, inhales, or eats any part of the plant.  These symptoms include intense thirst and eventually a coma.  It can also lead to death in humans in some cases.

9. Pokeweed

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When eaten, Pokeweed can poison humans and cause nausea, stomach pain, vomiting, diarrhea, low blood pressure, incontinence, and thirst, as well as other serious symptoms.  It is also likely to be very unsafe for a human to touch Pokeweed with their bare skin so it is advised that you avoid it at all costs.

10. Yew

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It is important to be aware of the risks of the Yew plant.  In fact, every part of the plant is poisonous and can cause really severe and painful stomach issues.  It can also affect the heart rate and cause it to speed up and slow down dangerously.  And, amongst other severe and dangerous symptoms, it can also cause confusion and hallucinations.

11. Hemlock

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Hemlock poisoning has been found to affect the nervous system, including the paralysis of the motor nerve ends.  It can also cause vomiting, trembling, and problems with the movement of the body.  And in severe cases, symptoms can lead to a coma and even eventually to death.

12. Oleander

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Oleander flowers each year but despite its appearance, can be fatal to humans.  This is because the plant contains certain chemicals called toxic cardiac glycosides that have been found to affect the heart in dangerous ways including slowing the heart rate right down.

13. Castor Bean

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The Castor seed has a potentially deadly outer coating.  This hard coating contains a deadly chemical called ricin.  And the ingestion of ricin can be fatal to humans.  Symptoms of ricin poisoning can also include vomiting and diarrhea, stomach pains, dehydration, shock, damage to internal organs like the liver and kidneys, and eventually, death.

14. Milkweed

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Like the Oleander plant, Milkweed also contains toxic cardiac glycosides, and when ingested, these can prove fatal to humans.  These chemicals not only slow the heart rate right down, but they can also cause stomach problems, confusion, seizures, and respiratory paralysis.

15. Belladonna

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If ingested, like a lot of these deadly plants, Belladonna has been found to be likely poisonous to humans.  In fact, if a human eats any part of the Belladonna plant, they might experience blurred vision, hallucinations, convulsions, and, in serious cases, coma.

16. Water Dropwort

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Water Dropwort can affect the nervous system in humans.  It has been found to decrease the nerve signals to the brain and can cause unconsciousness.  There are also early symptoms of Water Dropwort poisoning including vomiting, dizziness, blood in your pee, turning blue and convulsions so seek medical attention if you believe this deadly plant has been ingested.

17. Datura

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Every single species of Datura are toxic to humans and they have also been found to be psychoactive.  And all parts of the plant are poisonous but the flowers and the seeds are the most poisonous of all.  Common symptoms of poisoning are hallucinations, psychosis, and even death if ingested.  It's important to state that this isn't an exhaustive list of symptoms.

18. Rhododendron

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The Rhododendron plant, when ingested, can cause death in humans in extreme cases and if a person has been exposed, they're going to need to get to the hospital fast for cardiovascular support.  Other symptoms include, but this is not an exhaustive list, vomiting, cardiac arrhythmias, and seizures.

19. Lily-of-the-valley

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Lily-of-the-valley has been found to be extremely toxic to humans.  And they contain chemicals that also affect the human heart.  In fact, the leaves, flowers, and fruit of the plant are poisonous to humans and can cause cardiac distress, and can even be fatal when ingested in large quantities.

20. Aconite

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When ingested or exposed to bare skin, Aconite is a really fast-acting poison.  When exposed to the plant, humans, in severe cases, can actually die from Aconite poisoning.  Other symptoms also include vomiting, diarrhea, breathing, and heart problems.

21. Fall Crocus

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Fall Crocus has occasionally been mistaken for edible plants like onions, wild garlic, and leaks, and therefore eaten.  And when they are eaten, it causes poisoning with some really nasty symptoms.  These include a burning sensation in the mouth, sickness and diarrhea, liver and kidney damage, blood and nerve problems, and even death.

22. Bracken Fern

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Bracken Fern is said to grow all over the globe except Antarctica and has been linked to tumor growth in humans, as well as bone marrow depression and blindness to name a few.  It can also impact livestock like cattle if they eat a lot of it and they may experience bone marrow damage and bleeding.

23. Elderberry

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Although when ripe, Elderberries are edible when they are unripe, they contain a really harmful chemical called cyanide which can cause nausea, sickness, and diarrhea.  This is also true for the leaves and other parts of the plant.  So, if you're picking Elderberries, make sure they're not green and hard.

24. Woody Nightshade

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Interestingly, the stem of Woody Nightshade has been found to be likely safe to consume.  But the fruit and the leaves are poisonous to humans and when ingested can be fatal in huge amounts.  Other symptoms of poisoning can occur too including sickness and diarrhea, nausea, and convulsions.

25. Stinging Nettle

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Stinging Nettles can cause itchy and painful rashes if their leaves directly touch bare skin.  But if used correctly, they can actually be consumed safely.  Sometimes though, symptoms do occur such as mild stomach upset, sweating, and fluid retention so make sure you do your research!

26. Poison Hemlock

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Poison Hemlock, when ingested, can cause some really unpleasant symptoms of poisoning in humans and if it is ingested in large quantities, it can prove fatal or lead to a coma.  And amongst other symptoms of poisoning, Poison Hemlock can affect the nervous system and cause paralysis of motor nerve endings.

27. Virginia Creeper

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If you have sensitive skin, the sap from the Virginia Creeper can cause you to have an allergic reaction if it comes into contact with your skin.  And it is important to know that the berries of the plant are, in fact, poisonous when ingested because they contain oxalic acid which is mildly toxic to both humans and dogs.

28. English Ivy

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Allergic reactions and symptoms of poisoning generally occur when English Ivy is ingested.  These include stomach upset, hives, rashes, and difficulty breathing.  English Ivy is toxic to cats, dogs, and livestock though and it is important to keep an eye on children under 5 who are more likely to be exposed to plant poisoning.

29. Boxwood

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The ingestion of Boxwood has potentially life-threatening symptoms that include seizures and paralysis.  If a person consumes Boxwood in any dose, it can negatively affect the nerves, and the respiratory system and even cause digestive disorders which can be very dangerous.

30. Lily Pollen

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The whole of the Lily plant is toxic to humans, including pollen, flowers, leaves, and stems.  The pollen can also cause allergic reactions and cause itchy sinuses.  But it's also important to understand that the pollen of a Lily is extremely toxic to cats and dogs so it is best avoided if you have a beloved pet.

31. And Now.. The Most Dangerous Things You Can Find In Your Garden! Legionella Bacteria

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Legionella bacteria is known to hide in potting soil that many people innocently use for the gardens and garden plants. There have been cases of people catching legionellosis through handling the potting mixture. There are warnings on the packet, but it always pays to be careful!

32. Tetanus (Lockjaw)

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Tetanus, also known as lockjaw, is something else known to be lurking hidden in soil, which means it's a risk for every gardener. Although it can be rare, it's still a possibility. Even the smallest scratch can risk tetanus, and that's what makes it so risky for a gardener who's bound to get a scratch or two!

33. Pesticides And Fungicides

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Chemical and non-chemical pesticides and fungicides are also something to think about when you're working on your garden or land plot. They can be dangerous even if they're simply stored in the wrong way, and especially if you have children, as well as being a fire hazard.

34. Insect Stings

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We all know how annoying it is when we're trying to relax in the garden only to have a bee or wasp flying our heads! If you're anything like us, you'll run back into the house screaming, but that doesn't change the fact that insect stings are some of the biggest threats in the garden!

35. Insect Bites!

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And of course with garden insects comes those pesky insect bites, too. Especially if you're in mosquito territory! It's pretty impossible to spend time relaxing in your garden, or do some gardening work, without suffering at least one insect bite on your legs or arms! (Warning: next up is a bit of a jumpscare!).

36. Spiders, Of Course

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Spiders are bound to be found in your garden, especially if it's a large garden with lots of rocks, trees and shrubbery. While most species of spider will leave you well enough alone, places which have the funnel web spider are in for a fun (and risky) ride.

37. Gardening Tool Trip Hazards

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Another serious danger when it comes to gardens can be all the trip hazards. If you have garden decorations, stones and pathways, this is going to be a trip hazard anyway, but when you have a mountain of gardening tools, the risk just go up a serious percentage!

38. Or, Worse, Serious Accidents

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And depending on what kind of tools you have, the danger can go from a simple fall to something life-threatening if you're not careful. If you're using heavy gardening machinery like trimmers and saws, then there's a risk of cutting yourself severely if you're not being wary!

39. Harmful UV Rays

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And the reason that most people enjoy their garden: the sun! Which is of course a blessing and a curse. While spending all day in your garden, busying yourself with important jobs, it can be easy to forget the dangers of spending too long in extremely hot temperatures and in direct sun and you remember you didn't put any sun screen on.

40. The Back Injury Potential

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The back injury potential is even higher when it comes to gardening, because you're more than likely going to be carrying something heavy. Whether it's a massive sack of potting soil from your car trunk to your lawn, or the latest heavy flowerpot you've bought, there's always serious risk of straining yourself!

41. Lawnmowers

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Of all the 'heavy machinery' when it comes to gardening, lawnmowers have to be the most dangerous, whether it's a handheld one, or a driveable one. There are plenty of accidents you can get into with one of these bad boys, including fatal ones if you're not too careful.

42. Overgrown Lawns

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The issue with wildly overgrown lawns is that you don't know what's lurking inside! This makes it a huge risk if you can't remember things like where you left that sharp gardening tool that you might accidentally step on. Keep your lawn freshly cut so you can always see what's going on!

43. Plenty Of Bumps And Scrapes

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Gardening is a very hands on hobby, of course, which means you're literally going to get injuries on your hands most likely. You can expect a lot of cuts, bumps and scrapes when it comes to gardening - at best, they'll be painful, at worst, they might carry infections, or worse.

44. Bugs Carrying Diseases

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When out in the garden, you also need to watch out for bugs which may be transporting diseases. Ticks that carry Lyme Disease are a well known threat for people exploring out and about, or even just in the garden depending on if your area is prone to them. So always check yourself before you go back into the house!

45. Dehydration

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It's very easy to get carried away when you're gardening all weekend, which means stopping for a water break is probably the last thing on your mind when those plants need potting! Especially under the heavy daytime sun, you're going to run risk of dehydration very quickly.

46. Pushing Yourself Too Far Physically

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There's no doubt you risk overexerting yourself and suffering serious injuries when it comes to pushing yourself too far with gardening. We know what it's like when you just want to get something done - and when you DIY it instead of hiring in the professionals - but you could risk injuring yourself or burning yourself out.

47. Exposing Yourself To Dangerous Noise Levels

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If you're using very loud power tools without wearing the proper hearing protection, then you could risk seriously damaging your ears. Power tools like trimmers, chippers and mowers can reach high decibels, and anything over around 80 (which most of them are) can risk damaging your hearing.

48. Water Feature Risks

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If you have a very large garden with a water feature like a pond, there's always a risk of drowning if you have young children about, so this is definitely something to watch out for. Saying that, there's no reason it's not a risk for adults either - if you fall in and can't get yourself out, for whatever reason.

49. Repetitive Strain Injury

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Gardening is seen as a very fulfilling and relaxing hobby, but there's no denying that it's strenuous - and repetitive at that. Most gardening tasks will require repetitive motions with your hands and arms, like digging and planting, and this can run the risk of repetitive strain injuries in the long-term.

50. Dangers For Dogs

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Last but not least, there are many dangers in gardens that could be risky for dogs rather than humans. If you have a garden, it's likely you also have a four-legged friend, too. But things like weed killers, certain plants, lawn feed and even certain mushrooms that grow in the ground can all pose a risk if your dog comes into contact with them.