22 Common Poisonous Plants

Use these pictures to identify poisonous plants that might be lurking in your backyard. This guide features common toxic plants found in North America and will help you recognize vegetation that can be dangerous if touched or ingested. The toxicity levels can vary significantly, so exercise caution before planting or handling the following 22 examples.

Warning

Always be extremely careful when removing toxic plants; it's best to hire professionals instead of attempting to do the work yourself.

Bittersweet Nightshade

Bittersweet nightshade (Solanum dulcamara) is a common woody weed and is particularly hazardous to children due to its brightly colored berries. While the berries pose the highest risk if ingested, all parts of the plant (bark, leaves, sap) are toxic. The fast-growing vine is often mistaken for American or Oriental bittersweet plants.

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Chinese Lanterns

Related to bittersweet nightshade, the Chinese lantern (Physalis alkekengi) plant's leaves and fruit are toxic. Popular among craft enthusiasts, the fruit's husk starts green, turns yellow in late summer, and becomes a deep orange by fall. These colorful pods are often used in dried floral arrangements and wreaths.

Foxglove

Foxgloves (Digitalis spp.) are tall, flowering biennials that thrive in dry, shady spots. They bloom with clusters of tubular, often speckled flowers that range in color from purple to white. Deer and rabbit-resistant, all parts of the plant (flowers, leaves, roots, and stems) are highly toxic if ingested by humans.

Mountain Laurel

Mountain laurel (Kalmia latifolia) is common in eastern North America's countryside or can be purchased at nurseries, including the beautiful 'Minuet' laurel. It, along with azaleas and rhododendrons (Rhododendron spp.), belongs to the heath family and has toxic bark, sap, leaves, and flowers.

Castor Bean

Castor bean (Ricinus communis) is a tropical plant often grown as an annual in northern climates, particularly in potted arrangements for patios. While the plant itself is attractive, it produces castor oil, a laxative, and ricin, a deadly toxin.

Yew

Yew (Taxus spp.) bushes can grow in sun or shade, making them a versatile landscaping option. However, their bright-red berries contain a toxic seed, and the needle-like leaves are harmful to humans and animals.

Poison Sumac

Both the leaves and berries of poison sumac (Toxicodendron vernix) are toxic. This plant gives all sumacs a bad reputation despite most being harmless and beautiful in fall. Poison sumac has leaves with seven to 13 leaflets (an odd number), a red stem, and white berries.

Poison Ivy

Poison ivy's (Toxicodendron radicans) toxicity comes from an oil called urushiol. While the leaves are the most toxic part, any contact with any part of the plant should be avoided, even in winter. Burning poison ivy can release urushiol in the smoke, causing severe reactions.

Easter Lily

Gardeners in northern climates can't expect Easter lilies (Lilium longiflorum) to bloom outdoors much earlier than July, unlike store-bought ones forced to bloom for the holiday. The sap from the stems and leaves can be toxic to humans, but Easter lilies and 'Stargazer' lilies are especially harmful to cats.

Stinging Nettles

Stinging nettles (Urtica spp.), as the name implies, should be avoided while gardening. They can cause a painful reaction upon contact. Don't confuse them with dead nettles, which are perennial ground covers.

Yellow Dock

The ASPCA lists dock (Rumex sp.) as toxic to dogs, with low toxicity to humans. Dock, also known as sorrel, is easy to identify late in the season when its flower heads look like dried coffee grounds.

Lantana

Lantana (Lantana camara) is a popular annual plant in cold climates and a shrub in warmer areas. Its colorful flower clusters are attractive but the berries, leaves, and sap are toxic.

Lily-of-the-Valley

Lily-of-the-valley (Convallaria majalis) is often used in weddings for its bell-shaped, fragrant white flowers. Despite its delicate appearance, it's toxic in large amounts and can become invasive.

White Baneberry

Anytime you see "bane" in a plant name, it's likely toxic. Baneberry (Actaea) is a herbaceous perennial in the buttercup family. It comes in both red and white forms, with the latter often called "doll's eyes."

Tansy

Common tansy (Tanacetum vulgare) was once valued as an herb but is now known to be toxic to people and animals. Its small, golden button-like flowers are attractive but ingesting any part of the plant is harmful. Tansy is often mistaken for the equally toxic tansy ragwort (Jacobaea vulgaris).

Poison Oak

Poison oak (Toxicodendron diversilobum) has three leaves similar to poison ivy and oak tree-shaped leaves that turn red in the fall. The plant also produces white berries. To eradicate, pull it up by the roots while wearing protective gear or use herbicides. Contact with poison oak can cause a severe skin rash.

Oleander

Oleander (Nerium oleander) is an easy-growing, fragrant shrub used for hedging. However, it’s highly toxic to humans and animals if touched or ingested. Plant oleander far from areas children or pets frequent, and wear protective clothing when handling it.

Mistletoe

Mistletoe leads a double life as a festive holiday decoration and a parasitic plant that attaches to trees and shrubs. Several types of mistletoe are toxic to humans and animals when ingested, with American mistletoe (Phoradendron serotinum) being less toxic than European mistletoe (Viscum album). Keep mistletoe out of reach from children and pets.

Jimsonweed

Jimsonweed (Datura stramonium) is highly toxic to both humans and animals when ingested. It has thick purple stems, large trumpet-shaped flowers, and a foul smell. With shallow roots, it can be easily removed.

Poison Hemlock

Poison hemlock (Conium maculatum) is extremely toxic and also invasive. It resembles Queen Anne’s lace in its first year and can be identified in its second year by its reddish-purple streaked stems. Removal involves diligent mowing and chemical treatments. Never burn or compost poison hemlock; dispose of it in a sealed garbage container.

Wild Parsnip

Wild parsnip (Pastinaca sativa) is a tall plant with yellow flowers and celery-like leaves. Frequently found among poison hemlock, it should never be touched as it is highly toxic to humans and animals.

Giant Hogweed

Giant hogweed (Heracleum mantegazzianum) grows up to 20 feet tall, often resembling Queen Anne’s lace. It has stems with purple spots and some hair, and its leaves are large and deeply incised. Both humans and animals should avoid contact due to its extreme toxicity.

What to Do If You Touch a Poisonous Plant

Here are the steps to take if you come into contact with a toxic plant:

• Immediately rinse your skin with rubbing alcohol, poison plant wash, or a degreasing dishwashing soap or detergent, and lots of water. Scrub under your nails using a brush. Keep rinsing frequently to prevent the solution from drying on your skin or spreading the urushiol (oily resin in poisonous plants).
• Apply wet compresses, calamine lotion, or hydrocortisone cream to reduce itching and blistering.
  
• Seek immediate medical attention if you experience a severe allergic reaction, difficulty breathing, or swelling on your body or face.

FAQ

What plant is the most toxic to humans?

Belladonna (Atropa belladonna) is considered one of the most toxic plants to humans and animals, mainly due to its sweet-tasting fruit. Fortunately, it’s not very common in the United States, where it has been found in only a few states, typically in disturbed soils like dumps and roadsides. Monkshood is another highly toxic plant often found in gardens; it can be fatal if ingested. Gardeners should wear gloves when handling it. Foxglove, also mentioned earlier, is among the most toxic plants to humans.

What are some common characteristics used to identify poisonous plants?

One common characteristic to identify poisonous plants, such as poison ivy and poison oak, is the number of leaves