Poisonous Plants: Geographic Distribution | NIOSH (2024)

FAQs

Poisonous Plants: Geographic Distribution | NIOSH? ›

One or more of the most common poisonous plant species are found throughout the United States (except Alaska and Hawaii). These plants can be found in forests, fields, wetlands and along streams, road sides, and even in urban environments, such as, parks and backyards.

Poison Hemlock: Deadly invasive species rapidly spreading across the US. Poison hemlock is a toxic invasive species that has been quickly spreading around the U.S. The entire plant is poisonous and can be deadly if eaten.

Poison ivy (A) usually has three broad, tear-shaped leaves. It can grow as a climbing or low-spreading vine that sprawls through grass. It is found everywhere in the United States except Alaska and Hawaii. It often grows along rivers, lake fronts and ocean beaches.

Toxicodendron diversilobum (syn. Rhus diversiloba), commonly named Pacific poison oak or western poison oak, is a woody vine or shrub in the sumac family, Anacardiaceae. It is widely distributed in western North America, inhabiting conifer and mixed broadleaf forests, woodlands, grasslands, and chaparral biomes.

One or more of the most common poisonous plant species are found throughout the United States (except Alaska and Hawaii). These plants can be found in forests, fields, wetlands and along streams, road sides, and even in urban environments, such as, parks and backyards.

Oleander (Nerium oleander) is a common ornamental evergreen shrub. It is used as a freeway median divider in warmer states, such as California. This plant is extremely toxic, and a single leaf may kill an adult.

napellus, also known as monkshood or wolfsbane) is a perennial herb often grown as an ornamental plant due to its attractive blue to dark purple flowers. All parts of the plant, especially the roots, contain toxins. Aconitine is the most dangerous of these toxins.

Closely related to poison hemlock (the plant that famously killed Socrates), water hemlock has been deemed "the most violently toxic plant in North America." A large wildflower in the carrot family, water hemlock resembles Queen Anne's lace and is sometimes confused with edible parsnips or celery.

To eradicate poison oak and poison ivy chemically, use an herbicide that contains glyphosate, triclopyr, or a 3-way herbicide that contains 2,4-D amine, dicamba, and mecoprop.

Is poison ivy found in all 50 states? ›

Recognizing Poison Ivy, Poison Oak, and Poison Sumac

Poison Ivy: Found throughout the United States except Alaska, Hawaii, and parts of the West Coast.

As for the poison ivy plant, it's found throughout every state in the U.S. except California. The species has been found occasionally in The Golden State, but in general, poison ivy doesn't do well in the Mediterranean-like climate of California.

Poison sumac

It is found in wooded, swampy areas, such as Florida and parts of other southeastern states. It is also found in wet, wooded areas in the northern United States. Poison sumac: Has 7 to 13 leaflets on each leaf stem.

Poison oak grows along the West Coast and in the Southeast and is rarely found in the Midwest. The southeastern variety (Atlantic poison oak) looks very similar to poison ivy. Poison oak often grows in wooded areas, grasslands, and coastal scrub areas.

Poison hemlock is native to Europe, northern Africa and western Asia. It was introduced to North America in the 1800s as a garden plant. This plant spreads by seed and is present in most states in the continental United States. Visit EDDMapS for the current distribution opens in a new browser tab of this species.

Closely related to poison hemlock (the plant that famously killed Socrates), water hemlock has been deemed "the most violently toxic plant in North America." A large wildflower in the carrot family, water hemlock resembles Queen Anne's lace and is sometimes confused with edible parsnips or celery.

Poison Ivy

Fall leaves are yellow, orange and red. The plant produces small, greenish-white clusters of flowers in spring and white, waxy, berry-like fruits in fall. It grows almost everywhere in Texas except for the western Panhandle and in almost any type of environment.