About Commonly Used Poisonous Landscape Plants

Learn about poisonous commonly used landscape plants.

Many of the most commonly used landscape plants are poisonous. While most people do not regularly dine on the decorative greens growing in their yards, toxic plants can be a silent hazard to children and pets.

Plants can poison in a variety ways. Many plants must be consumed in order to be poisonous; others cause a reaction when they come in contact with the skin. Some plants only have portions that are toxic.

Poisonous plants do not necessarily need to be removed from a yard; however, it is important to know which plants may present a danger in order to educate the people exposed to them and to ensure no one is placed in danger. Remember to teach children never to put any part of a plant in their mouths without checking with a parent.

The following are some of the most widely used poisonous plants:

Black nightshade: Black nightshade is a low growing, leafy plant with small white flowers and dark berries. While all portions of the nightshade plant are considered poisonous, the berries are especially toxic, especially when they are unripe. Black nightshade is prevalent in most of the United States.

Chinaberry: This deciduous tree has small and abundant lilac-colored flowers and small yellowish, wrinkled berries. The fruit, flowers and leaves are all toxic, but only if large quantities are eaten. It is native to North America and is widely used as an ornamental planting.

Dieffenbachia: A green leafy plant with white or yellow mottled leaves, dieffenbachia is commonly used as a houseplant and in temperate landscapes. Since dieffenbachia causes severe mouth pain if it is eaten, it is unusual for someone to ingest enough for it to be toxic.



Elephant's Ear: The large, hardy and attractive leaves of elephant's ear make it a popular choice for many landscapers. Eating elephant's ear will cause extreme mouth swelling and pain and can be toxic in large amounts.

Foxglove: Foxglove is popular for its elegant tubular flowers. Also known as snapdragons, foxglove has highly toxic compounds in its leaves and stem.

Larkspur: This beautiful flowering ornamental has long stocks and clusters of blue, purple and white elongated flowers. Even small amounts of this plant are highly poisonous if ingested; it can cause nausea, respiratory system paralysis, convulsions, muscle weakness and death.

Lily-of-the-valley: This tiny member of the lily family has fragrant blooms and can slow the pulse when ingested. All portions of the plant are toxic.

Narcissus: Also known as the daffodil, narcissus is a flowering plant with white, yellow and red blossoms. The stems are barren of leaves, making these a stark ornamental. While the narcissus is only toxic when ingested in large amounts, even limited skin exposure can cause a mild to severe skin rash.

Oleander: An evergreen flowering shrub, the oleander is often used as a barrier hedge. All portions of the oleander are considered poisonous. All portions of the plant are toxic even if consumed in small quantities.

Philodendron: Philodendrons are native to warm areas of the United States and are commonly used in landscaping. They are also extremely common as houseplants. The plants are toxic to humans and common houseplants and are especially poisonous to cats.

Rhododendron: The flowering rhododendron shrub is commonly found across the United States. The shiny leaves and brightly hued flowers make it an attractive landscape plant. The entire plant is poisonous if ingested.

Squill: The squill, also known as scilla, has long slender leaves and purple or white bell-shaped flowers. It can cause minor skin irritation when touched and can be fatal if eaten.

Wisteria: Wisteria's climbing vines are popular for their clusters of fragrant flowers. Wisteria produces a flat pod with highly toxic seeds.

Yew: The bark, leaves and seeds of the evergreen yew are poisonous. Often cultivated as a woody shrub, the yew can cause pain, pulse slowing, convulsions and even death when eaten.

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