10 Toxic Summertime Plants

Foliage to Keep Away from Pets

Our green thumbs often reappear during the warmer seasonal months, as we are inspired to banish dull winter months with bright, blossoming plants and flower beds.

For those of us with dogs and cats, however, which of these plants should we yield caution to and prevent accidental poisoning?

We asked the Pet Poison Helpline to help identify the most toxic summertime plants for pets.

Popular Summertime Plants Harmful to Pets

According to the Pet Poison Helpline, the top 10 most dangerous summertime plants for cats and dos during the months of June through August include:

  • Autumn crocus (Colchicum autumnale)
  • Azalea/rhododendron (Rhododendron species)
  • Castor bean (Ricinus communis)
  • Foxglove (Digitalis species)
  • Lilies (Lililum species) - cats only
  • Lily of the Valley (Convallaria majalis)
  • Oleander (Nerium oleander)
  • Sago palms (Cycads, Macrozamia, and Zamias)
  • Yesterday, Today, and Tomorrow (Brunfelsia species)
  • Yew (Taxus species)

In some cases, the entire plant is toxic but in some cases it may just be the seed, leaf or petal of the plant that is poisonous.

Dr. Ahna Brutlag, the director of Veterinary Services and a senior veterinary toxicologist at Pet Poison Helpline further explains that when it comes to plants, there's a surprising number of toxins, some of which impact all animal species and others which only impact certain ones.

“The types of toxins in plants are extremely diverse and often function as aprt of the plant's defence mechanism. For example, foxglove contains cardiotoxins, Yesterday, Today, and Tomorrow is neurotoxic, sago palms cause liver damage, and the autumn crocus contains a cellular poison. Certain plants such castor beans, foxglove, yew, oleander, and the autumn crocus can exert their toxic effects on nearly all animal species, including people. Others, such as lilies (true lilies or Lilium species), are only known to be toxic to cats.”

Choose Fertilizer Wisely

Did you know organic fertilizers can be dangerous to pets, too?

While they’re a great natural source of nitrogen and utilize unused animal products, they’re often made of bone, blood or feather meal. These strong, appealingly-scented ingredients are very enticing to dogs and will often be eaten along with the poisonous bulbs.

Depending on the amount of meal-based fertilizer ingested, they can cause an obstruction in the dog’s stomach, and also lead to severe vomiting, diarrhea and pancreatitis.

Signs of Toxic Ingestion

If you suspect your dog or cat has ingested a toxic plant, contact your veterinarians or the Pet Poison Helpline immediately (1-855-289-0358). At Pet Poison Helpline, experts in veterinary toxicology are available 24-hours a day to provide both you and your veterinarian with instant advice regarding toxic doses and treatments.

Cat in flower field

Signs that your dog or cat may have ingested a toxic plant include:

  • Decreased heart rate
  • Diarrhea
  • Increased heart rate
  • Lethargy  
  • Pancreatitis
  • Seizures
  • Severe cardiac arrhythmias
  • Vomiting
Pet Poison Helpline

Vulnerability to plant toxicities depends on pet species, amount ingested and the size of your pet.

It is probably best not to have any poisonous plants around pets. Sprays sold in pet stores or nurseries to keep pets away from plants are often not very effective.


About Pet Poison Helpline

Pet Poison Helpline is a 24/7 animal control services available for pet owners and veterinary professionals who require assistance with treating a potentially poisoned pet. Their experts can consult on all toxins and all species. Pet Poison Helpline is the most cost-effective animal poison control services and is available in North America, Canada, and the Carribean by calling 855-289-0358 or go to PetPoisonHelpline.com.