What plants can we not eat? A guide to identifying toxic flora

Less than one percent of the world's known plant species are estimated to be poisonous to humans. Identifying these plants is important for safety, especially for children and pets.

Quick Summary

This article details plants toxic to humans and pets. It covers common garden varieties and wild species. The article provides information on identifying these plants and outlines safety measures to prevent accidental consumption.

Key Points

• Identify and Isolate: Learn to recognize common poisonous garden and houseplants like Oleander, Foxglove, and Philodendron, and keep them out of reach of children and pets.

• Be Wary of Lookalikes: Be cautious when foraging, as toxic wild plants like Water Hemlock can easily be mistaken for edible species like parsnips.

• Know the Toxic Parts: Remember that even with plants like yew and tomatoes, specific parts can be deadly while others are safe, so educate yourself on which parts to avoid.

• Prevent Accidental Ingestion: Never assume a plant is safe just because animals eat it; different species have different tolerances to toxins.

• Act Quickly in Emergencies: In cases of suspected poisoning, immediately contact your local poison control hotline and be prepared to identify the plant involved.

• Avoid All Unidentified Plants: When in doubt, do not eat. This simple rule is the most effective way to prevent accidental poisoning from unknown or wild plants.

The Hidden Dangers in Your Garden and Home

While many plants add beauty and vibrancy to homes and gardens, some contain toxins as a natural defense. Misidentification or curiosity can lead to accidental poisoning. Understanding which plants pose a risk is the first step toward creating a safer environment.

Common Toxic Garden and Landscape Plants

Several landscaping plants are highly toxic and should be handled with care. Some of the most common include:

• Oleander (Nerium oleander): Highly poisonous with lethal cardiac glycosides throughout the plant. Can cause severe heart problems, vomiting, and potentially death.
• Foxglove (Digitalis purpurea): Contains cardiac glycosides that affect the heart and can be fatal if ingested.
• Rhododendron and Azalea (Rhododendron spp.): Contain grayanotoxins, causing nausea, low blood pressure, and heart rhythm issues.
• Yew (Taxus): The berries and leaves contain highly toxic alkaloids that can be fatal.
• Lily of the Valley (Convallaria majalis): Contains cardiac glycosides that can cause vomiting and reduced heart rate.

Dangerous Wild Plants to Avoid

Foraging requires expert knowledge due to deadly lookalikes. Be aware of:

• Water Hemlock (Cicuta maculata): One of North America's most toxic plants, containing cicutoxin that causes violent convulsions and can be fatal.
• Poison Hemlock (Conium maculatum): All parts are highly poisonous, containing toxins that affect the nervous system. Can be mistaken for Queen Anne's Lace.
• Deadly Nightshade (Atropa belladonna): Shiny black berries contain toxic alkaloids that can cause paralysis and death.
• White Snakeroot (Ageratina altissima): Contains trematol, which can be passed through milk and cause "milk sickness".

Toxic Houseplants to Keep Out of Reach

Common houseplants can also be toxic. Examples include:

• Philodendron (Philodendron spp.): Contains calcium oxalate crystals causing mouth irritation.
• Pothos (Devil's Ivy, Epipremnum aureum): Also contains calcium oxalate crystals, causing irritation and swelling.
• Dieffenbachia (Dumb Cane): Causes intense mouth and throat pain and swelling.
• Sago Palm (Cycas revoluta): Particularly the seeds are dangerous, causing vomiting and liver failure in pets.

Comparison Table: Edible vs. Toxic Lookalikes

Distinguishing between safe and dangerous plants is crucial. Here's a comparison of common lookalikes:

Feature	Water Hemlock (Cicuta maculata)	Queen Anne's Lace (Daucus carota)
Stem	Smooth, hollow, often spotted with purple.	Solid, hairy, and green.
Flowers	Flat-topped clusters of small white flowers.	White flowers with a single dark reddish flower in the center.
Roots	Thick tuberous roots with high toxin concentration.	Single, tapered taproot, like a carrot.
Toxicity	Extremely toxic, potentially fatal.	Not toxic, but can cause skin irritation.
Scent	Strong, unpleasant smell.	Carrot-like smell.

Immediate Actions After Suspected Poisoning

If plant ingestion is suspected, act fast:

1. Do not induce vomiting unless advised by a professional.
2. Immediately call poison control or emergency services. In the U.S., call 1-800-222-1222.
3. Identify the plant if possible and save a sample.
4. Remove any remaining plant material from the mouth or skin and rinse with water.

Conclusion

Knowing what plants can we not eat is essential for safety. Exercise caution with garden plants, houseplants, and when encountering wild flora. When in doubt about a plant's safety, it's best to avoid it. Consult resources like the Poison Control Center website for more information.

Note: This article is for informational purposes and not medical advice. Always contact a healthcare provider or poison control in case of suspected poisoning.

Frequently Asked Questions

Which common garden plants are toxic to pets?

Many common garden plants are toxic to pets, including Oleander, Azaleas, Daffodils, Lilies, and Foxglove. For cat owners, certain lilies are extremely toxic and can cause kidney failure.

Can poisonous plants cause skin irritation simply by touching them?

Yes, some poisonous plants can cause skin irritation, blistering, or dermatitis upon contact. Examples include Poison Ivy, Poison Oak, Giant Hogweed, and the sap from Dieffenbachia.

Is it true that the leaves of a rhubarb plant are poisonous?

Yes, while the stalks of rhubarb are edible, the leaves contain high concentrations of oxalic acid and are considered poisonous. Eating the leaves can cause kidney issues and other symptoms.

What should I do if my child eats a poisonous plant?

Immediately call your local poison control center or emergency services. Do not induce vomiting unless instructed to do so. Try to identify the plant and save a sample for medical personnel.

How can I tell the difference between edible Queen Anne's Lace and deadly Poison Hemlock?

Queen Anne's Lace has hairy, solid stems and a single, small red or purple flower in the center of its white flower cluster. Poison Hemlock has a smooth, hollow, purple-blotched stem and no red flower in the center.

Are all parts of a poisonous plant toxic?

Not necessarily. In some plants, like the yew, only specific parts are toxic (the seeds and leaves), while the rest is not. However, it's safest to assume the entire plant is a risk unless you are absolutely certain.

Are houseplants safe to have with pets and children?

Many common houseplants are toxic. If you have children or pets, it is best to research the specific toxicity of any plants you bring into your home and place any dangerous varieties completely out of reach. Safe alternatives exist for most toxic plants.