These popular species can be harmful if eaten, and a few shouldn't even be touched. Here's what to watch out for.

By Jenny Krane
Updated August 19, 2020
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Word has traveled fast about giant hogweed, a toxic plant that can be mistaken for Queen Anne's lace, a related but harmless species that also grows wild across many areas of the United States. Aside from weedy plants, certain plants commonly grown in gardens and landscapes have poisonous chemicals in their leaves, berries, and stems. Here are a handful of dangerous plants to be aware of, especially if you have kids and pets around. Don't feel like you have to rip them all out, though. As long as you take a few precautions such as wearing gloves when handling them, you can continue to enjoy them in your garden.

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'Hardy Pink' oleander nerium
Credit: Chipper R. Hatter

1 Oleander

Oleander is a dense flowering shrub with narrow pointed leaves that is hardy in USDA Zones 7 and warmer. Attractive pink, white, or red flowers bloom in summer. All parts of oleander are toxic if ingested, including dried flowers and sap. Contact with the foliage and flowers can also cause skin irritation, and smoke from burning debris is toxic to breathe.

Related: How Should I Trim Back My Oleander?

yew shrub
Credit: Matthew Benson

2 English Yew

These tough evergreen shrubs are tolerant of many conditions, including drought, shade, sun, and soggy soil, plus they are usually avoided by deer and rabbits. They are an ideal choice for creating hedges and foundation plantings. All parts of English yew are poisonous except the fleshy part of its red berries (the seeds within the berries are still toxic).

'MacDonald' rhubarb
Credit: Bob Stefko

3 Rhubarb

The ruby red stalks of this perennial plant make delicious pies, crumbles, and tarts. But beware: Rhubarb leaves contain high amounts of oxalic acid, which can cause a burning sensation in the mouth and throat when eaten, as well as nausea, vomiting, and kidney problems. You would need to eat several pounds of the leaves to reach lethal levels but to avoid any unpleasant side effects, make sure to cut off the green leafy parts from the red stalks as soon as possible after harvesting and toss them in your compost bin.

Related: Grow Rhubarb in Your Garden

pink foxglove flowers
Credit: Peter Krumhardt

4 Foxglove

Foxglove is a summer-bloomer that has long been a cottage garden favorite. The tube-shape flowers come in many colors and patterns, attracting bees and other pollinators. Some chemicals in foxglove are used in heart medications, but eating any part of this plant could cause the heart to slow too much or beat irregularly.

white moonflower blooms
Credit: Mike Jensen

5 Devil's Trumpet

This shrubby plant is usually grown as an annual, though it is hardy in Zones 9 and 10. Devil's trumpet is also known as thorn apple because of the spiny, round fruits that follow the white, trumpet-shape, summer flowers. All parts of the plant are poisonous if eaten, especially the leaves and seeds.

monkshood aconitum carmichaelii blooms
Credit: Lynn Karlin

6 Monkshood

Bluish purple blooms that resemble a helmet or monk's cowl grace this perennial in late summer. Monkshood, also known as wolf's bane, contains several toxins that can cause deadly gastrointestinal, respiratory, and heart issues if swallowed. Even the sap on your skin can be dangerous so always wear gloves and long sleeves when working around this plant.

Purple Castor Bean
Credit: Ed Gohlich

7 Castor Bean

These dramatic perennials are frost-tender, so are usually grown as annuals in cold climates. They still can grow up to 5-6 feet in a year, taking on the appearance of a small tropical tree with large, lobed, reddish purple leaves and pincushion-like seedpods. Castor bean contains the deadly compound ricin in all parts of the plant, especially the seeds. Two more warnings: The sap may cause skin sensitivity, and the pollen of the blooms is highly allergenic.

detail of lily-of-the-valley pieris andromeda
Credit: Bill Holt

8 Lily of the Valley

Fragrant, bell-shaped, white flowers appear among the green leaves of this shade-loving, perennial groundcover in spring. Eating any part of lily of the valley can cause blurry vision, digestive issues, and altered heart rhythm.

Related: Make a Lily-of-the-Valley Pocket Pot

Comments (1)

Anonymous
July 26, 2019
Overall the article is very good regarding the toxic properties of these plants. I do question the comments regarding the English Yew -Taxus baccata. This plant will die in soggy soil and deer love to feed on it.