Garden Plants Poisonous to Dogs and Cats

It’s natural to want to share your gardening fun with your pets. Unfortunately, there are a lot of common garden plants that are poisonous to cats and dogs. If you have any of the following plants, vegetables or herbs growing in your garden, keep an eye on your pets when they’re out there with you, especially if they’re young—puppies and kittens (just like babies) love to put things in their mouths that they shouldn’t!

Common Garden Plants That Are Poisonous to Cats and Dogs

Tomato Plants

Plants Poisonous to Dogs and Cats: Tomatoes

The most common garden plant that is poisonous to cats and dogs is the tomato plant (Lycopersicon spp). Grown in practically every vegetable garden around, tomato plants are surprisingly toxic and can cause a shockingly long list of pet health issues (like severe gastrointestinal upset, weakness, slow heart rate and diarrhea). Signs of ingestion include hypersalivation, loss of appetite, confusion, behavioral changes and dilated pupils. And, although ripe tomatoes are rarely toxic to pets, plant material is. Note that just because tomato plants are toxic to pets doesn’t mean you can’t grow them, however, especially since tomatoes are one of the garden vegetables you can grow vertically (okay, fine, fruit!).


Another common garden plant that is toxic to pets is rhubarb (Rheum rhaponticum). Rhubarb is so toxic to cats and dogs, in fact, that it can cause kidney failure, tremors and coma (although rarely death) if consumed in adequate amounts. Luckily, growing rhubarb doesn’t need to be on your naughty list: Although the leaves are toxic (as well as bitter and unappetizing), the stalks are safe. And, since the leaves taste so bad, pets rarely eat them in toxic quantities.


Plants Toxic to Dogs and Cats: Garlic

A powerful Allium well-known for its medicinal and health benefits, garlic can also be incredibly toxic (and not just to pets). Garlic is poisonous to both cats and dogs, and warning signs of toxic ingestion include panting, blood in urine, vomiting and weakness. If you’re a fan of homemade and/or all-natural treats and your recipe calls for garlic, be sure to limit amounts to low, low levels (as the precise amount that is toxic to your pet may be influenced by species, breed and size). And, if you’re exploring garlic as a natural de-wormer, be sure to monitor your pet for symptoms of poisoning like panting, vomiting and weakness, as mentioned earlier.

Flowering Plants That Are Poisonous to Pets


Plants Toxic to Pets: Dianthus

Dianthus (Dianthus caryophyllus, also known as Pinks, Sweet William, Carnation and Wild Carnation) is another popular garden flower that is poisonous to both cats and dogs. Luckily, Dianthus is only mildly toxic and symptoms of ingestion are limited to gastrointestinal distress and mild dermatitis.


Another extremely popular and widely available plant that is toxic to pets is geranium (Pelargonium sp.) Easily identified by its strong scent and bi-colored leaves, geranium contains at least two sweet-smelling but toxic chemicals (Geraniol and linalool) that can produce vomiting, anorexia, depression and dermatitis in pets.

Bulbs (Lilies, Tulips, Irises, Daffodils, Peonies, Dahlias, and more)

Plants Toxic to Pets: Tulips

Few people realize that some of the most popular flowering bulbs are poisonous to cats and dogs. In fact, according to the ASPCA, bulbs that are poisonous to pets include autumn crocus, daffodils, dahlias, lily of the valley, hosta, hyacinth, peonies, irises, narcissus, tulips and quite a few more. While most pets aren’t likely to nibble on these plants, dogs that dig and puppies who don’t know any better may dig up the bulbs and eat them. This is of special concern because the bulb is the most poisonous part of the plant and can be fatally toxic.

Herbs and Medicinal Plants That Are Poisonous to Cats and Dogs


Plants Toxic to Animals: Chamomile

Beloved by herbalists and natural-cure followers, chamomile (Anthemis nobilis, also called Feverfew, ground apple and turkey weed) is an herb that can be quite toxic to cats and dogs. In fact, essential oils and acids are strong enough to cause skin irritation just on contact, and ingestion can lead to vomiting, diarrhea, anorexia and various allergic reactions.

Spanish Thyme

While there aren’t many popular herbs that are poisonous to pets, those that are make up for it by being especially toxic. Case in point: Spanish Thyme (Coleus amboinicus, also known as Mexican mint, Indian borage, Stinging thyme, French thyme, Indian mint, country borage, Jamaic thyme, and broadleaf thyme). The essential oils in this toxic-to-pets herb can cause vomiting, diarrhea, depression, anorexia and bloody stools.

When it comes to plants that are poisonous to cats and dogs, this is just the tip of the iceberg. For a comprehensive list of toxic and non-toxic plants, visit the ASPCA website. Or, for other non-pet related gardening-related resources and articles, visit my Gardening Guides page, and remember to keep an eye on the pets in your garden!

Images thanks to Ajith Kumar, Dwight Sipler, choking sun, Dennis Wong and Toshiyuki IMAI.

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