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10 Ways Plants Try to Defend Themselves from Being Eaten

by Andrew Gestalt
fact checked by Rachel Jones

Plants are absolutely an underrated species. We don’t think of them as having their own survival mechanisms or defense strategies, but many of them do. That’s how they’ve been able to survive for thousands of years. We’ve dug deep to find these ten ways plants try to defend themselves from being eaten. We’ll also explore how they defend themselves from bug infestations and even fungus growth. You’ll be surprised at what these plants can do… it’s kind of a big dill.

Related: 10 Cases Of Bioluminescence Used For Defense And Deception

10 Corn Plants

Q&A – Are the wasps on my corn beneficial?

Everybody loves corn—it has the juice! But did you know that corn plants can intentionally attract wasps? When corn plants are damaged, they release chemical compounds that act as a distress signal and literally attract wasps to the plant. These chemicals are called terpene synthase, which are enzymes that form the sesquiterpene scent compounds released by the plant. And those wasps are crazy for it.

The wasps are attracted to the scent and can help protect the corn stalks by destroying pests. Some species of parasitic wasps even lay their eggs inside the bodies of pests like caterpillars, which eventually kills the pest and helps control their population.

It’s definitely giving children of the corn vibes. But, hey, whatever keeps those delicious golden cobs safe!

9 Lithops or Pebble Plants


Sometimes, the best defense is a great costume. And that definitely holds true for this plant.

Lithops, also known as pebble plants, have a remarkable adaptation that allows them to resemble stones, effectively blending into their arid and rocky surroundings. This natural disguise serves as a rock-solid defense against hungry herbivores.

But that’s not the only thing they can do. Their disguise pairs really well with their survival skills. Lithops dedicate a significant portion of their structure to water storage. Their fleshy leaves, resembling rocks in appearance, act as reservoirs for storing water. This adaptation enables the plants to survive in regions experiencing severe drought, where water scarcity is a constant threat.

Oh, and lithops have a pretty unique method of reproduction. As self-sterile organisms, they rely on pollination to produce seeds. The seeds are enclosed within a hydrochastic fruiting capsule, consisting of 4 to 8 chambers. These capsules only open when they come into contact with moisture, including raindrops. Consequently, rain plays a crucial role in dispersing the seeds, as it splashes them away from the parent plant, ranging from a few inches to several feet. Once the capsule dries, it closes again, safeguarding any remaining seeds until the next rainfall event.

So its classic rock costume keeps it safe from being eaten and keeps it hydrated and reproducing while it’s hiding out. That’s one advanced rock.

8 Asparagus Berries

ASPARAGUS HAS A FRUIT (Asparagus fern) – Weird Fruit Explorer

No matter how good the stalks taste covered in hollandaise sauce, remember that asparagus berries are dangerous. The berries of the asparagus fern contain sapogenin, a steroid that is toxic to dogs and cats. This acts as a defense mechanism, reminding animals that they shouldn’t eat the plant. Well, that goes for most animals.

However, if a dog or cat ingests these berries, vomiting, diarrhea, and/or abdominal pain can occur. Allergic dermatitis (skin inflammation) can occur if an animal is repeatedly exposed to this plant. And rapid ingestion of more than five to seven ripe berries can induce abdominal pain and vomiting. So keep asparagus fern berries away from pets and children to avoid accidental ingestion!

The treatment for asparagus berry poisoning in humans can vary depending on the severity of the symptoms. If you suspect that you or someone you know has ingested asparagus berries, seek medical attention immediately. Here are a few general guidelines for treating asparagus berry poisoning in humans:

  • Induce vomiting: If the berries were ingested recently, inducing vomiting may help remove the berries from the stomach. Do not induce vomiting if the person is unconscious or having convulsions.

  • Drink fluids: Drinking fluids can help flush the toxins out of the body.

  • Seek medical attention: If the symptoms are severe, seek medical attention immediately. The doctor may administer activated charcoal to absorb the toxins or provide other treatments as necessary.

7 Broccoli

Why you shouldn’t eat too much broccoli or kale | NewsNation Special Coverage

Arguably one of the tastiest veggies (and it’s fun to turn them into little trees), broccoli seems totally harmless. But this power plant has a devious way of defending itself against being eaten.

Broccoli contains sulforaphane. Sulforaphane is a natural plant compound found in many cruciferous vegetables like broccoli, cabbage, cauliflower, and kale. In the broccoli plant, sulforaphane is a natural protection against pests and diseases.

Luckily for humans, sulforaphane is an excellent addition to your diet. The compound is known to exhibit chemoprevention by various mechanisms and has protective effects on cells from oxidative stress. Sulforaphane is also an antioxidant that cancels out free radicals and reduces inflammation.

Sulforaphane is heat resistant, so cooking broccoli does not destroy its health benefits. Broccoli is considered a good source of sulforaphane, which has been linked to improved heart health and digestion.

6 The “Shy Plant” or Mimosa Pudica

Growing the Sensitive Plant (Mimosa pudica)

If you’re an introvert, you’ll definitely relate to this plant’s defense mechanism.

The Mimosa pudica plant, commonly known as the sensitive or shy plant, safeguards itself against predators and environmental pressures. The leaves of this plant are covered in small hairs that exhibit heightened sensitivity to touch, temperature, and motion. When its leaves are touched, they close, folding inward and giving the appearance of a lifeless plant. This folding of leaves deters predators, as they are less likely to perceive the plant as a potential food source. They also close during the night—it’s important to get a good night’s sleep, even if you’re a plant.

Chemical defense is another strategy you’ll see in the Mimosa pudica plant. When the roots of this tropical flowering plant are disturbed, it emits an unpleasant odor reminiscent of a bodily function. Basically, it has a sulfuric smell. This olfactory response functions as a vegetational alarm system, deterring potential threats. It can also activate or enhance these skills in response to predation or other stressors, providing adaptive protection.

Additionally, the sensitive plant has the ability to communicate with neighboring plants by releasing volatile organic compounds (VOCs). These compounds serve as warning signals to nearby plants, inducing physiological reactions that help them prepare for impending crises.

So they might be shy, but they still stay involved in their plant community.

5 Chili Peppers

How Chilis Got Spicy (and Why We Love the Burn)

Can you handle the heat? Chili peppers are betting that you can’t.

Well, they’re more concerned about avoiding fungus than being eaten. But the principle is still the same.

The spiciness of chili peppers is actually a defense mechanism that some peppers develop to suppress a microbial fungus that invades through punctures made in the outer skin by insects. The fungus is from a large genus called Fusarium that destroys the plant’s seeds before they can be eaten by birds and widely distributed. The chemicals that make these peppers so spicy are called capsaicinoids, and they protect them from fungal attack by dramatically slowing microbial growth.

In other words, be grateful for the burning heat in your grandpa’s hot sauce. It’s keeping the fungus away!

4 Coffee Plants

COFFEE PLANT CARE INDOORS | why you have brown leaves! | coffea arabica

Half the world relies on caffeine to make it through the workday. But did you know that caffeine is just as important to coffee beans?

Caffeine is a natural pesticide used by the coffee plant to protect itself from pests and other competing plants. Caffeine has potent antibiotic and anti-fungal powers and causes sterility in several insects. That’s quite the offensive tactic there, coffee.

Caffeine also permeates the soil, which surrounds the plants by accumulating fallen leaves and berries, inhibiting the growth of competing plants. Caffeine also provides protection under the soil, protecting the plant from bacteria and fungi. But in doing this, the caffeine plant ultimately kills itself as well. Over many years, the accumulation of caffeine in the soil becomes so great that the toxicity level is high enough to harm the parent plant.

I guess there really can be too much of a good thing.

3 Foxgloves

Foxglove – Digitalis purpurea – Growing Foxglove

Foxgloves are one of those plants where you’ll want to stay far, far away, no matter how exquisitely beautiful they are. Ingestion of any parts of this plant can result in severe poisoning. The poisonous substances found in foxglove plants include deslanoside, digitoxin, and digitalis glycoside. Symptoms include nausea, headache, skin irritation, and diarrhea. In severe cases, it can even lead to visual and perceptual disturbances and heart or kidney problems.

Foxgloves that are attacked by animals or insects or subjected to stressful conditions such as drought or microbial infection can also warn other plants by releasing VOCs, just like the Mimosa pudica.

But believe it or not, they’re not all bad. Foxglove plants contain toxic cardiac glycosides that are used medicinally to treat heart failure.

2 Potatoes

Did You Know That Potato Plants Have Poisonous Fruit?!

Mashed, baked, or fried, we love potatoes in every form. But watch out—these hearty starches are prepared to protect themselves. The potato plant has a few options to fight back against pests and diseases. It produces a range of chemical compounds that serve as deterrents to herbivores and pathogens. One of these compounds is solanine, an alkaloid with toxic properties. Ingesting large quantities of solanine can lead to digestive issues and even be lethal to both humans and animals.

The potato plant possesses trichomes, which are tiny hairs on the leaves. These trichomes deter animals from feeding on the plant. And if they do, potatoes can increase the production of chemical compounds, or VOCs, as a response.

It can also protect itself from the fungal pathogen Verticillium dahliae, which causes a condition known as ”early dying.” The potato plant produces proteins that stop the fungus from growing. Nothing ruins Thanksgiving like fungus in your mashed potatoes.

1 Yuca or Cassava Root

Your Guide to Eating this Toxic Root

One of the primary defense strategies of the yuca or cassava root is the presence of cyanogenic glucosides. The roots, peels, and leaves of the cassava plant contain two cyanogenic glucosides known as linamarin and lotaustralin. These compounds are broken down by linamarase, a natural enzyme found in cassava, releasing hydrogen cyanide (HCN). Like a mother-in-law, the toxicity of cassava can vary. Some will seem more bitter or sweet, depending on how much of these compounds are present in the root.

But scientists are hoping to change that. They’re using genetic modification techniques, like CRISPR, to engineer cassava with reduced levels of cyanide. By manipulating the plant’s genetic makeup, researchers want to create cassava varieties with lower toxicity levels, enhancing its nutritional value. Through selective breeding, breeders have also successfully cultivated cassava plants that are more resilient to deterioration after harvest, resulting in better quality and longer shelf life.

I know what you’re thinking. “Why do they even sell yuca if it’s so dangerous,” right? Well, by the time it reaches your dinner plate, it (hopefully) should be prepared in a way to make it safe to eat.

Traditional practices include fermentation, which involves soaking cassava roots, and drying cassava roots. Many people also pound cassava leaves and cook the mash. You can also boil cassava leaves for an extended period, and ensiling cassava peels has proven to be an efficient technique for reducing cyanide content in them.

Don’t be afraid of giving the yuka a chance in your meal plan this week. It’s not going to kill you—hopefully.

fact checked by Rachel Jones