Gardeners Beware: Experts Warn These 9 Poisonous Flowers Might Be in Your Backyard

CNET

21-07-2025

With summer now well and truly here, you're probably spending more time in your backyard or garden than you would through the rest of the year. The warmer weather also means that new plants and flowers are blooming, and all of that extra color is always welcome, right? But did you know that some plants aren't as safe as they might look? In fact, you might be surprised just how many common plants and flowers could be dangerous to you, your family and even your pets. In this article, we enlist the experts to help us explore some common toxic plants and flowers that often go unnoticed in your backyard
How to spot poisonous flowers
Spotting poisonous flowers can be tricky since toxic plants are often visually appealing. However, certain characteristics can help you identify them. For example, bright colors, distinct smells or specific shapes of flowers.
"Find out what poisonous plants are likely to occur in your region through reliable resources such as your state department of environmental conservation or local cooperative extension office. Learn the key features of those plants so you can recognize them," says Emily Detrick, director of horticulture at the Cornell Botanic Gardens.
"When gardening or recreating in an area with unfamiliar plants, we recommend using a plant ID app such as PlantSnap or PictureThis in combination with a field guide for your region. This is a great way to not only verify if a plant may be one to avoid but also to learn about and appreciate the many beneficial plants you are likely to encounter," she says.
10 poisonous backyard flowers to watch out for
Water hemlockWater hemlock is one of the most poisonous plants in North America. The plant has small white flowers that grow in umbrella-like clusters, making it easy to confuse with other wildflowers. The plant contains a toxic substance, cicutoxin, which is a poisonous, unsaturated alcohol with a carrot-like smell. It is mainly concentrated in the tubers (roots) but can also be found in the stems and leaves during early growth. Water hemlock grows primarily in wet meadows, pastures and along the banks of rivers.
Cicutoxin is a serious convulsant, which means it can cause severe seizures and even death. Touching water hemlock can cause irritations, so you have to be careful if you get near the plant. You should immediately contact a poison control center or nearby emergency department if you or someone else has unknowingly come in contact with the plant or your child or pet has eaten it. Symptoms of poisoning, such as rapid breathing, high heart rate or dilation of pupils, often start quickly, and death may occur as early as two to three hours after the onset of symptoms, suggesting prompt action is crucial.
HydrangeaHydrangea is a popular ornamental shrub known for its large, showy flowers. The flowers, typically blue, pink or white in color, are arranged in large clusters at the end of branches, with each flower having four to five petals. Hydrangea is usually found in the eastern and southeastern US and grows in moderately moist forests, along streams or rocky areas.
Hydrangea contains a toxin called amygdalin, a type of cyanogen glycoside. If eaten, cyanogen glycoside can break down into toxic hydrogen cyanide upon metabolization, leading to symptoms such as nausea, vomiting and diarrhea, especially in children and pets such as dogs and cats. In some cases, simply brushing against the plant may cause skin irritation. You must immediately contact your doctor if your child or pet has accidentally ingested any part of hydrangea since all parts of the plant are poisonous.Monkshood, also known as wolfsbane, is an ornamental plant best known for its blue to dark purple flowers. Monkshood typically grows in wet meadows, stream banks and near seep springs, often forming large patches. It is found in isolated regions in the US, including New York, Ohio, Iowa and Wisconsin. All parts of the plant, especially roots, seeds and flowers, contain a poisonous toxin called aconitine. Aconitine is primarily known as a heart poison but can also affect the nervous system. Poisoning occurs due to accidental ingestion by children and pets, leading to symptom onset within a few minutes to a few hours.
If you or someone you know has consumed monkshood, do not try to make the person vomit. Instead, contact poison control or visit a nearby emergency department immediately. Quick action is essential since the toxin can be life-threatening.
Lily of the valleyLily of the valley is a shade-loving flowering plant known for its white bell-shaped flowers with a strong, sweet fragrance. While it may charm your garden, you must remember that the plant is highly poisonous. In North America, lily of the valley contains toxic cardiac glycosides, which may be dangerous if ingested. All parts of the plant contain the toxin, and even a small amount can cause serious health problems such as irregular heartbeat, gastrointestinal problems and even seizures.
It is important to wear gloves and protective clothes while interacting with the plant. You must also keep your children and pets away from lily of the valley since ingestion may be fatal to them. If you suspect contact or ingestion, call your poison control center or visit an emergency department immediately.Oleander is an evergreen shrub commonly found in Southern America and other warm parts of the US. Oleander flowers are pink or white and often occur in clusters. All parts of the plant are poisonous and have cardiac glycosides that can cause serious symptoms such as nausea, vomiting and irregular heart rhythm upon ingestion. Even touching the plant can cause skin irritation and dermatitis in some people.
"Poisonous flowers such as oleander are not particularly dangerous to touch but should not be eaten. If a child were to put one into their mouth, I would suggest calling poison control at 800 222 1222," says Michael Levine, emergency medicine physician at UCLA Health. Contact poison control or a nearby doctor if you or someone you know has unintentionally ingested any part of oleander. Children and pets also need to be taken to a doctor if they accidentally ingest any part of oleander.Rhododendron is a well-known evergreen shrub native to eastern and southeastern North America. It bears rose to white colored flowers that are either bell or funnel-shaped. Rhododendron grows best in moist, acidic and well-drained soils, especially in areas with moderate temperatures.
However, it is important to know that all parts of rhododendron contains the poisonous grayanotoxins that can lead to symptoms of confusion, irregular heart rate and low blood pressure. You must call poison control if your child or pet accidentally puts flowers or leaves in their mouth. However, simply touching the plant may not be particularly dangerous, Levine says.
FoxgloveFoxglove is an attractive plant known for its bell-shaped flowers that come in shades of white, pink, cream yellow or rose in color. It is found widely across the US, mostly in cool, temperate climates. Even though it adds beauty to gardens, all parts of foxglove contain a poisonous toxin, cardiac glycosides, mostly digoxin. Ingesting flowers, leaves, stems or seeds of the plant could lead to irregular heartbeat, low blood pressure, confusion and drowsiness. Ingesting even small amounts of foxglove can be deadly for children or pets if ingested. You must call poison control or visit a doctor if you or someone you know has come in contact with foxglove.Jimsonweed, also known as thorn apple, is a poisonous plant that was originally found in Central America but is now found throughout the US. The flowers are large trumpet-shaped, with colors ranging from white to lavender. All parts of the plant are considered poisonous due to the presence of alkaloids atropine, hyoscyamine and scopolamine. Ingestion of leaves, flowers or stems can lead to serious symptoms, including rapid heart rate, hallucinations and dry mouth. Jimsonweed is also poisonous to pets and livestock. Call poison control or visit a nearby emergency department if you or your child ingests jimsonweed unknowingly.
Deadly nightshadeDeadly nightshade, also known as belladonna, is a plant that is native to Europe but can now be found in parts of the US, mostly in New York and three West Coast states, Washington, Oregon and California. The plant grows in shady and wet regions. The flowers are bell-shaped and purple in color. The plant is highly poisonous due to the presence of psychoactive tropane alkaloids in all parts of the plant. Ingestion of any part, even in small amounts, can lead to symptoms such as vomiting, hallucinations, rapid heart rate, dilated pupils and even death. Brushing skin against the plant can also lead to the absorption of toxins through the skin or severe dermatitis. You must visit an emergency department immediately if you, your child or your pet comes in contact with the plant.
How do you treat exposure to poisonous plants?
Treatment for exposure to poisonous flowers depends on the type of flower, the type of exposure (skin or ingestion) and extent of exposure. Skin irritations may be relieved by using cold compresses or treated by using hydrocortisone creams or antihistamine medications. If you think you have ingested or had exposure to a poisonous plant, seek medical attention for any life-threatening symptoms (coma, seizure, breathing difficulties).
"If you are not having life-threatening symptoms, call your regional poison center for immediate advice (1-800-222-1222), and they will determine the next course of action depending on the plant, amount and patient clinical status," says Shireen Banerji, director of the Rocky Mountain Poison Center at Denver Health.
You can keep children away from such poisonous flowers by keeping indoor plants out of their reach and watching them closely while they play in the backyard. You can protect yourself by wearing gloves or protective clothing while handling an unknown plant.
The bottom lineSeveral flowers that may add beauty to your backyard may be poisonous, causing serious health problems for you, your child or even your pet. When interacting with a poisonous plant or its flower, you must call poison control. You should also wear gloves and protective clothing while handling an unknown flower. Keeping children and pets away from such plants is also essential since the ingestion of some of them may even cause their death.