9 Dangerously Poisonous Plants to Avoid in Arizona

Written by Nixza Gonzalez
Updated: April 24, 2023
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No one wants to accidentally touch a poisonous plant or eat one, especially when visiting a new and unfamiliar place. Arizona is a beautiful state with lots of different flora and fauna, but which are safe, and which are dangerously poisonous? Follow along to learn more about 9 dangerously poisonous plants to avoid in Arizona and why.

1. Candelabras Cactus (Euphorbia ingens)

Candlestick Cactu

A tall succulent tree that grows about 19 to 26 feet tall.

©abriendomundo/Shutterstock.com

Candelabras cactus is a common name for two plants. One is not poisonous and is native to Baja California in Mexico. However, the poisonous candelabras cactus is the Euphorbia ingens, which is native to southern Africa. Candelabras cactus produces white milky latex which is dangerous. It irritates the skin and can be deadly for pets and humans when ingested. Candelabras cactus is a tall succulent tree that reaches about 19 to 26 feet tall. The stems of this plant have five ridges. On the tips of the ridges sit small greenish-yellow flowers. Typically, the flowers bloom from autumn to winter and the plant produces a red fruit that turns purple as it ripens. It’s a common houseplant in Arizona and grows well in the climate because the candelabras cactus prefers dry lands and semi-savannas and needs little water.

2. Oleander (Nerium oleander)

oleander

This poisonous plant can lead to nausea, abdominal pain, excessive salivation, and diarrhea.

©iStock.com/Katrin_Timoff

Oleander is a shrub, or small tree, associated with the Mediterranean Basin. However, because it’s been widely cultivated, the precise origin is unknown. Oleander plants are beautiful and produce stunning pink, red, and white flowers in clusters. This shrub can grow up to 20 feet tall. The leaves grow in pairs or whorls of three and are thick, narrow, and deep green. Some oleander plants have a sweet scent, but the scent is a distraction. Oleander plants are toxic. Adults aren’t at risk for oleander poisoning, but should not purposefully ingest this plant as it contains two toxic compounds, oleandrin, and oleandrigenin. This poisonous plant can lead to nausea, abdominal pain, excessive salivation, and diarrhea. These symptoms are most common in dogs, cats, horses, and small children. In fact, in 2000, two toddlers died from eating oleander leaves from the neighbor’s yard. Oleander is toxic to the heart.

3. Jimsonweed/Devil’s Weed (Datura stramonium)

Jimson Weed

Although death is uncommon, devil’s weed intoxication produces bizarre behaviors, insomnia, nausea, hallucinations, urinary retention, and amnesia.

©Melinda Fawver/Shutterstock.com

Don’t let the name fool you, the devil’s weed, also known as jimsonweed is a beautiful flowering plant of the nightshade family Solanaceae. At first glance, it doesn’t look poisonous, but all parts of the plant contain toxicity. This plant is thought to originate from Central America, but grows all around the world, including Arizona. It’s an invasive weed and spreads quickly. Devil’s weed grows in a bush form and reaches up to 5 feet tall. The roots are long, thick, and white. The leaves are smooth and about 3 to 8 inches long. Jimsonweed has leaves with dark and light green surfaces. The leaves are bitter and cause nausea when ingested. During the summer, jimsonweed produces trumpet-shaped, white to creamy or violet flowers with a pleasant scent. Although death is uncommon, devil’s weed intoxication produces bizarre behaviors, insomnia, nausea, hallucinations, urinary retention, and amnesia.

4. Dumb Canes (Dieffenbachia)

Dumb cane

Because the plant is toxic and when ingested, some people temporarily lose the ability to speak.

©Rak ter samer/Shutterstock.com

Dumb cane is a genus, not a species. However, there are 56 confirmed species in the genus, many of which grow well in Arizona. Dumb canes also known as leopard lilies are native to the New World Tropics. Many people grow them as houseplants, but they thrive outside as well in some regions. However, they require a minimum of 41 °F to thrive. Dumb canes need healthy, fertile, and moist soil to grow. They also need plenty of light, but sunlight from a window is often enough. Another nickname for dumb canes is mother-in-law’s tongue. This is because the plant is toxic and when ingested, some people temporarily lose the ability to speak. The plant’s cells have needle-shaped calcium oxalate crystals which produce poisoning effects, however, the plant is rarely fatal. Instead, children under five years old are mainly affected and hospitalized.

5. Mexican Bird Of Paradise (Caesalpinia pulcherrima)

Mexican bird of paradise

As beautiful as this flowering plant is, you need to be careful around small children or pets.

©Aref Barahuie/Shutterstock.com

Caesalpinia pulcherrima, also known as the Mexican bird of paradise, and the peacock flower is a flowering plant in the pea. While the plant’s origin is unknown because of widespread cultivation, experts believe it’s native to the tropics and subtropics of the Americas and the West Indies. This beautiful shrub is common in Arizona and typically reaches about 9.8 feet tall. However, in Hawaii, the Mexican bird of paradise can reach 16.4 feet tall. This plant is vulnerable to the cold. Its leaves have 10 pairs of pinnae with leaflets. The flowers are bright red, yellow, or orange and are borne in racemes. As beautiful as this flowering plant is, you need to be careful around small children or pets. The plant produces seed-bearing fruit. The seeds contain tannic acid and when ingested cause discomfort and swelling in the mouth and tongue and gastrointestinal discomfort.

6. Silverleaf Nightshade (Solanum elaeagnifolium)

silverleaf nightshade

The flowers have five petals that unite, making the flowers look like stars.

©ervin herman/Shutterstock.com

Silverleaf nightshade is a plant native to parts of southwestern USA, including Arizona. The plant is also found in western North America but is considered a weed. You can also find silverleaf nightshade plants in South Africa and the Middle East. It reaches between 4 inches and 39 inches tall. Although the leaves and stems of the plant are green, they are covered in small downy hairs giving it a silver, or almost blue appearance. Silverleaf nightshades have 5 to 6-inch long leaves and produce beautiful pink-purple and blue flowers from April to August. The flowers have five petals that unite, making the flowers look like stars. Occasionally, the flowers are white with five yellow stamens in the center. These plants spread quickly and are toxic to many animals. It’s especially common in horses and causes ivermectin toxicosis.

7. Persian Cyclamen (Cyclamen Persicum)

Persian cyclamen flowering plant

Plant lovers typically grow these beautiful plants indoors as houseplants.

©Adrian Eugen Ciobaniuc/Shutterstock.com

The cyclamen persicum, also known as the Persian cyclamen, is a flowering plant that thrives in regions with an elevation of up to 3,900 feet above sea level. While the plants are common in the United States as decorative plants, they are native to south-central Turkey, Lebanon, and Syria. This flowering plant also grows in the Greek islands of Rhodes, Karpathos, and Crete likely because of monks. This plant is unique because of its deep green heart-shaped leaves. The fleshy leaves grow up to 6 inches long. Persian cyclamen flowers bloom from winter to spring. The flowers are white or pale pink with 5 small sepals and 5 upswept petals. Plant lovers typically grow these beautiful plants indoors as houseplants. They are toxic and dangerous to pets, but severe reactions are rare.

8. Colorado Desert Mistletoe (Phoradendron macrophyllum)

Phoradendron macrophyllum

This parasitic plant consumes nutrients from over 60 tree species including alder, walnut, ash, willow, and sycamore.

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Colorado desert mistletoe is native to the western United States and Northern Mexico. They are flowering plants in the sandalwood family. These plants aren’t picky and grow in elevations up to 5,500 feet. This parasitic plant consumes nutrients from over 60 tree species including alder, walnut, ash, willow, and sycamore. The plant produces long erect green branches and rounded or oval oppositely arranged leaves. Colorado desert mistletoe also has male and female flowers that differ in appearance. Female Colorado desert mistletoes produce white to light pink spherical berries. The berries are poisonous but rarely lead to severe symptoms. The plant is beautiful, but bitter, which warns animals.

9. Spectacle Fruit (Wislizenia refracta)

Wislizenia refracta

This plant has foul and bitter-tasting foliage, grazing animals avoid this plant.

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Last but not least is the spectacle fruit, which is a poisonous annual herb native to western North America, including Arizona and California. This plant has foul and bitter-tasting foliage, grazing animals avoid this plant. It is rarely eaten but can cause a tingling sensation in your mouth and gastrointestinal discomfort. While toxic, spectacle fruit is an important plant for honey production. This branching herb produces many mustard-yellow densely packed flowers.

Summary of 9 Dangerously Poisonous Plants to Avoid in Arizona

These plants are a feast for the eyes only!

RankPoisonous Plant
1Candelabras Cactus
2Oleander
3Jimsonweed/Devil’s Weed
4Dumb Canes
5Mexican Bird Of Paradise
6Silverleaf Nightshade
7Persian Cyclamen
8Colorado Desert Mistletoe
9Spectacle Fruit

The photo featured at the top of this post is © Nick Pecker/Shutterstock.com


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About the Author

Nixza Gonzalez is a writer at A-Z Animals primarily covering topics like travel, geography, plants, and marine animals. She has over six years of experience as a content writer and holds an Associate of Arts Degree. A resident of Florida, Nixza loves spending time outdoors exploring state parks and tending to her container garden.

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