Garden Plant Toxicity in Cats

Cats love to chew on plants. Many plants are harmless if ingested, but some can be toxic. It is very important to know what kinds of plants are in your garden and whether they are toxic to your feline friend. Almost 10% of all pet poison calls to the ASPCA Animal Poison Control Center in 2021 were related to eating plants.

How Are Garden Plants Toxic to Cats?

The toxicity of plants ranges from mild to severe, depending on the plant. In many cases, the plant may cause mouth irritation or gastrointestinal symptoms such as vomiting and diarrhea. Sometimes the toxin from the plant can cause heart problems, labored breathing, liver or kidney damage, seizures, and even death. Knowing which plant your pet ingested is crucial to determining the plant’s toxicity level and how to treat it.

In many plants, toxic parts include pollen, flowers, leaves, stems, roots, and bulbs. Also, different plants have higher levels of toxin in different parts. For example, the dangerous compounds in tulips are concentrated in the bulbs, whereas in lilies the pollen is highly toxic. 

Symptoms of Garden Plant Toxicity in Cats

Symptoms of garden plant toxicity in cats vary based on the type of plant, the part of the plant, and the amount the cat ingested. In many cases symptoms are immediate, but they can be delayed up to a few days. 

Common symptoms of garden plant toxicity in cats include:

• Vomiting with or without blood

• Diarrhea with or without blood

• Drooling

• Irritation to the mouth, tongue, and esophagus

• Difficulty swallowing

• Decreased appetite (anorexia)

• Abdominal pain

• Lethargy

• Increased drinking and urinating

• Breathing difficulty

• Abnormal heartbeat

• Tremors/Seizures

• Coma

Top 10 Garden Plants Toxic to Cats

The following are the 10 most toxic plants to cats, with their specific symptoms:

• Lily (Lilium and Hemerocallis): Lilies are one of the most dangerous and potentially life-threatening plants if ingested by your cat. All parts of the plant, including the pollen, are toxic. If your cat is exposed to lily pollen, wipe or bathe them to remove it from the fur. The toxic chemical in the plant is unknown, but even a small ingestion (1-2 petals or leaves) can result in severe kidney failure.  

• Sago Palm (Cycas revoluta): Sago palms are common in tropical and subtropical environments.  All parts of the plant are toxic, but the seeds (nuts) are the most toxic. The toxic compound is cycasin, which causes severe liver failure. Sago palms are extremely toxic and prognosis is poor if ingested.

• Oleander (Nerium oleander): Oleander is an outdoor flowering shrub. All parts of the plant are toxic, but the roots and stems are the most toxic. The group of toxins, called cardiac glycosides, may cause fatal heart arrhythmias. 

• Lily of the Valley (Convallaria masalas): Lily of the valley is not a true lily and does not cause kidney failure like lilies in the Lilium family. It is still very poisonous and can be deadly. All parts of the plant are toxic and contain cardiac glycosides. Severe toxicity symptoms include an abnormal heartbeat and seizures. 

• Azalea (Rhododendron spp.): Azalea plants range from small flowering bushes to large, woody shrubs. The entire plant is toxic, but the leaves are the most dangerous. The principal toxin (grayanotoxane) is extremely potent and can affect your cat’s brain, gastrointestinal, and cardiac functions. 

• Autumn Crocus (Colchicum autumnal): Autumn crocus blooms in the fall and is much more toxic than spring crocus. All parts of the plant are highly toxic and contain the alkaloid colchicine toxin. Ingestion of this deadly plant can cause severe symptoms including breathing difficulty, seizures, and kidney and liver damage.

• Cyclamen (Cyclamen spp.): Cyclamens are seasonal flowering plants. All parts of the plant are toxic, but the roots are especially dangerous. The toxin (saponin) causes irritation to the mouth, and a large amount of it can be fatal. 

• Daffodil (Narcissus spp.): Daffodils are flowering plants. While all parts of the plant are toxic, the bulbs are the most toxic and contain lycorine. A large ingestion of this plant can cause breathing difficulty and heart arrhythmias. 

• Kalanchoe (Kalanchoe blossfeldiana): Kalanchoe is a flowering plant. All parts of the plant contain cardiac glycosides called bufadienolides. The plant is not usually ingested in amounts large enough to cause serious clinical signs. Symptoms include drooling, vomiting, and diarrhea. 

• Tulip and Hyacinth (Tulipa spp. and Hyacinthus orientalis): Tulips and hyacinths both belong to the Liliaceae family. The entire plant is toxic, but the toxins are concentrated in the bulbs. Cats typically eat it in small amounts and only have mild signs of drooling, vomiting, and diarrhea. 

What To Do if Your Cat Ingests a Toxic Garden Plant

If your cat eats a plant, first try to determine what type of plant it is. If you are unsure, collect a sample of the plant to show your veterinarian. It is also helpful to inspect the plant to see how much and what part of the plant they ate. 

With that information in hand, call your veterinarian to discuss if your pet needs immediate attention. You can also call the Pet Poison Helpline at (855) 764-7661, or the ASPCA Animal Poison Control Center at (888) 426-4435 for more help identifying the plant and determining if your pet needs to go to the emergency room.   

Treatment of Garden Plant Toxicity in Cats

The veterinarian or pet poison center may want you to take your cat to the clinic or hospital if they think they may have eaten a toxic plant. 

It can be very difficult and often unsafe to induce vomiting in cats, so your vet may suggest decontamination options including administering activated charcoal to bind the toxins in the stomach. 

In mild cases, your cat may be treated for nausea and diarrhea as an outpatient. However, if your cat ingests a highly toxic plant or has severe clinical signs, they may need IV fluids and additional care at the hospital. 

A complete blood count, serum blood chemistry, and urinalysis may be recommended for a baseline evaluation and may be rechecked to look for kidney or liver damage. 

How To Keep Cats Safe From Toxic Garden Plants

Many cats love to be outside and may be tempted to nibble on your garden plants. You can keep them safe by doing the following:

• Have a supervised outside time on a harness with a leash or in a catio

• Research all plants you are planting outside and keeping inside your home to determine what is toxic and should be avoided

• Check this comprehensive list of plants when bringing a new plant home  

• Consider growing “cat grass” as a safe alternative

Featured Image: iStock.com/Nils Jacobi