Ten poisonous plants to keep away from your clients’ pets

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Updated Mar 28, 2024
Photo: Ike ofSpain/FlickrPhoto: Ike ofSpain/Flickr

We all love our four-legged friends and want them to enjoy the yard on beautiful days. But certain plants in the landscape can be a hidden or unknown danger. When getting ready to head to a lawn care or planting project, be sure to check and see if the homeowner has cats or dogs that run free in the yard. If so, take to heart these 10 plants that are highly toxic and poisonous to felines and canines.

Plants that primarily affect dogs

Tulips (Tulipa spp.)

Photo: Mahbub Islam/FlickrPhoto: Mahbub Islam/Flickr

Tulips contain allergenic lactones, and the bulbs are where the concentrated toxic principal lye is, so be sure to warn customers to watch their dog and make sure it’s not digging up the bulbs. When the bulbs are ingested or even just chewed on, it can irritate the tissues of the mouth and esophagus. Watch for vomiting, diarrhea, and profuse drooling. While there’s no specific antidote, local veterinarians can offer relief and support in the form of rinsing the mouth, subcutaneous fluids, and anti-vomiting medication. Depending on the number of bulbs ingested, symptoms can be more severe and could lead to an increase in heart rate and visible changes in respiration. If these signs occur, get to a veterinarian as fast as possible.

Photo: Laura Rose/FlickrPhoto: Laura Rose/Flickr

Daffodils (Narcissus poeticus)

Daffodils contain lycorine that has a strong emetic property, which can trigger vomiting. Ingesting any part of this plant can cause diarrhea, abdominal pain, vomiting and even respiratory depression or possible cardiac arrhythmias. Ingesting this plant can lead to more severe symptoms, so if the dog has been exposed to the plant or if symptoms begin to appear, talk to a veterinarian immediately.


Photo: Charles Bell/FlickrPhoto: Charles Bell/Flickr

Azaleas and Rhododendrons (Rhododendron sp.)

Even eating just a few leaves, flowers or even the nectar of an azalea plant can cause vomiting, excessive drooling, and diarrhea. If not treated quickly by a veterinarian, pets can fall into a coma and potentially die. High concentrations of honey made by the bees that feed on azaleas are where the toxic components can be found. This honey is typically referred to as “mad honey” because of the confusion it can cause to pets after ingesting. This causes very low blood pressure and irregular heart rhythm, which can be life-threatening.


Plants that primarily affect cats 

Amaryllis (Amaryllis spp.)

Photo: Liz West/FlickrPhoto: Liz West/Flickr

The leaves, bulbs, and stems of the amaryllis contain lycorine and phenanthridine alkaloids, which can induce vomiting, abdominal pain, diarrhea, hypotension (blood pressure dropping), excessive drooling, tremors, respiratory depression, and more. While the toxin is primarily concentrated in the bulbs if any of this plant is ingested seek the medical advice of a veterinarian. The more severe symptoms will occur if the pet has ingested a larger amount of the plant, but be sure to keep a close watch if it is suspected that they’ve tried even a small bit of it.


Photo: Rohan Singh/FlickrPhoto: Rohan Singh/Flickr

Chrysanthemum (Chrysanthemum sp.)

Chrysanthemums contain toxins such as sesquiterpene, lactones, pyrethrins, and other potential irritants. If ingested, these toxins can cause vomiting, hypersalivation, dermatitis, lack of coordination, and diarrhea. Depending on the size of the animal that ingests the plant and the amount ingested, symptoms can vary from species to species and size to size.


Lilies (Lilium sp.)

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Some types of lilies may not be deadly to pets, but all lilies do bring some form of issue to the garden when it comes to pet safety. Lilies such as the Peace, Peruvian, and Calla contain oxalate crystals that can cause tissue irritation to the mouth, pharynx, esophagus, and tongue, which can result in a mild case of drooling. A few of the more dangerous, and toxic, types include the Tiger, Day, Asiatic, Easter, and Japanese Show lilies. Even ingesting just a small amount can cause severe kidney failure. If you see the cat nibbling on a lily, advise your client to take the cat and the plant to their veterinarian as soon as possible. The sooner they bring the pet in, the faster vets can work to help them.


Plants that are harmful to both  

Castor bean (Ricinus communis)

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Castor beans contain the toxin ricin, a highly toxic component that inhibits protein synthesis, and can cause oral irritation, increase in thirst, diarrhea, vomiting, burning of the mouth and throat, convulsions, and kidney failure. Ingesting even one ounce of seeds can be lethal, and signs typically appear 12 to 48 hours after ingestion. Be on the lookout for loss of appetite, colic, weakness, thirst, sweating, trembling, difficulty breathing, loss of coordination, fever, and progressive central nervous system depression.


English ivy (Hedera helix)

Photo: Aaron Gustafson/FlickrPhoto: Aaron Gustafson/Flickr

While it does require ingesting a higher amount of English ivy for serious problems to arise, stay on alert when planting in an area you know your clients’ pets will potentially visit. English ivy contains the toxin triterpenoid saponins (hederagenin), and can cause vomiting, hypersalivation, diarrhea, and abdominal pain. The actual foliage is more toxic than the berries that adorn the plant, but all parts of the ivy can cause skin irritation, burning in the throat after eating the berries, fever, and a rash.


Photo: eyesogreen/FlickrPhoto: eyesogreen/Flickr

Oleander (Nerium oleander)

While they may be beautiful and eye-catching, the oleander is hazardous for animals and humans alike. Containing poisons such as digitoxigenin and neriin, this outdoor shrub’s leaves and flowers are extremely toxic if ingested and can cause diarrhea, severe vomiting, low blood pressure, weakness, blurred vision, hives, lethargy, irregular or slowing heart rate, and even death. If a pet has taken a bite of oleanders, talk to a veterinarian immediately.


Photo: Liz West/FlickrPhoto: Liz West/Flickr

Yew (Taxus spp.)

All parts of this plant, except the flesh of the berries, contain a complex of alkaloids called taxine A and B and the volatile oil ephedrine. Death can follow after only a few hours of ingestion, and in some cases no symptoms are present. If symptoms do occur, they can include difficulty breathing, vomiting, seizures, tremors, staggering, coldness, weak pulse, and collapsing. While the berries on yew are harmless, the seed is highly toxic.

For a more detailed list of poisonous plants for pets, click here.

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