Plant

8 Poisonous Trees to Make You Think Twice

01. Oak

Level of Toxicity 1/3
Toxic Parts Leaves and acorns

Poisonous Trees

Poisonous Profile:

Everyone should plant an oak tree in their lifetime. It’s the kind of long-term investment that can live on for hundreds of years. You can find lots of oak options like the popular white oak and red oak. Not every oak tree will reach that height of 80 feet, but it does need ample space. In due time, it will provide wonderful shade for picnics, reading, and relaxation.

Be Aware:

If grazing animals like sheep, horses, and goats eat a lot of leaves or acorns from oaks, they could absorb toxins that might cause kidney damage.

The Bottom Line:

Plant it but probably keep your horses and goats away from eating the dropped leaves and acorns.

02. Strychnine Tree

Level of Toxicity 3/3
Toxic Parts Seeds contain strychnine, which can be deadly to all.

Poisonous Trees

Poisonous Profile:

Be grateful that this tree isn’t native to North America; it’s one of the most deadly trees in the world, so it’s good that you can’t easily get your hands on it. This tree contains one of the most famous and age-old forms of poisoning: strychnine. In fact, its history is rich with people using it for that purpose, especially in the nineteenth century. The deadliness comes from the seeds, found in the large ball-sized fruit.

Be Aware

You pretty much need to stay away from this one. There’s a reason people used it to poison others.

The Bottom Line:

No. Just no.

03. Black Walnut

Level of Toxicity 1/3
Toxic Parts Roots and the nuts (but only to some)

Poisonous Trees

Poisonous Profile:

The black walnut can be a beautiful tree, and it doesn’t really harm humans. However, it’s not really popular among gardeners because it contains something called juglone, which can harm nearby plants. Sounds odd, right? A lot of people don’t even realize this about black walnuts, but then sometimes they have trouble getting plants to grow under it.

Be Aware:

Researchers say that the only livestock affected by the shavings of this tree are horses. However, the roots can also contain something called juglone, which can harm nearby plants.

The Bottom Line:

There are better backyard tree options out there, so skip this one.

04. Horsechestnut

Level of Toxicity 2/3
Toxic Parts The nuts in raw form contain a type of poison called esculin.

Poisonous Trees

Poisonous Profile:

This can grow to be a huge tree, which is relatively harmless. However, the nuts of these plants, which are green and spiky, can actually do a lot of harm in the right circumstance. Beneath those spikes lies a form of poison. You might have to work pretty hard to get to the poison of this plant, but you should probably still keep away as much as possible.

Be Aware:

If you make it past the nuts and consume them raw, side effects can include nausea, vomiting, headaches, convulsions, and even respiratory failure. It could even lead to death.

The Bottom Line:

There are other (and better) trees to grow instead.

05. Manchineel

Level of Toxicity 3/3
Toxic Parts All parts.

Poisonous Trees

Poisonous Profile:

This is definitely one of the most poisonous plants in the world, and you can’t really get your hands on it, which is a good thing. However, there could be a chance you’d come across it in Florida or other tropical areas, so it’s good to be aware of it. The entire tree contains toxins that can lead to death. Even just touching the tree (where you could come into contact with the sap) or breathing the air close to it could cause irritation to your skin or lungs. The fruit can look tasty, but remember there’s a reason that it also has the nickname “apple of death.”

Be Aware:

If you eat this fruit, there’s a good chance you won’t see another day. Even coming in contact with it can cause irritation, so stay as far away as possible.

The Bottom Line:

Run in the other direction.

06. Buckeye

Level of Toxicity 2/3
Toxic Parts All parts, including seeds, leaves, and bark

Poisonous Trees

Poisonous Profile:

If you happen to pay attention to botanical names, you’ll notice that this one shares part of its name with the horsechestnut. They are closely related, even though the common names are quite different. This plant is very popular in certain parts of the country (like Ohio for the Ohio Buckeyes).

Be Aware:

If ingested, you might see signs of depression, twitching, inflammation, and vomiting. Especially keep an eye on pets that might be in an area where the seeds might have dropped onto the ground.

The Bottom Line:

You might want to reconsider it if you have pets that like to graze in the backyard.

07. Black Locust

Level of Toxicity 1/3
Toxic Parts All parts

Poisonous Profile:

You might be tempted to grow this tree when you see the beautiful flowers it produces in the spring, but just say no. While it’s not the most toxic tree available, it does have some annoying habits that gardeners don’t like. It produces lots of suckers, or little roots and offshoots from the main tree. These can be a pretty big pain to deal with in your landscape.

Be Aware:

Any animal that eats parts of this tree could experience vomiting, nausea, and other problems. Kids could be harmed if they get hold of the bark and chew on it. Otherwise, most cases involve livestock eating the bark or the seeds.

The Bottom Line:

Pick a different tree to grow in your backyard.

08. Rubber Tree

Level of Toxicity 1/3
Toxic Parts All parts have toxic elements.

Poisonous Trees

Poisonous Profile:

Did you know rubber is a natural substance that comes from trees in the wild? It is! This plant is native to Asia, where rubber tree plantations are common. Trees in the wild can reach more than 100 feet, but on plantations, they usually only get to 20 or 30 feet. The way you extract the liquid, called latex, from this tree is similar to the way they tap maple trees for syrup here in the United States. They drill into the trunk of the tree and then collect the liquid that drips out. After twenty or thirty years, rubber trees don’t really produce anymore, and they’ll likely get cut down. But knowing about this tree is pretty cool, right? While it’s only mildly toxic, think about all the things that have rubber in them!

Be Aware:

You likely won’t come in contact with this plant, but you might want to make sure you don’t have an allergy to latex because it could cause irritation.

The Bottom Line:

If you can find it (you probably can’t), then sure. Go ahead and grow it.

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