Ask the Edmonds Vet: Plants that are toxic to pets, Part 1

By Dr. David Gross

This column is the first in a series with information about plants toxic to dogs, cats and horses.

I found my kitten chewing on a houseplant, is this dangerous?

Maybe. The most important aspect of potential poisoning, from any source, is dose. How much was the animal exposed to per pound of body weight?

Kittens and puppies will chew on almost anything. Mainly because of their size, young animals are more susceptible to toxic substances. Fortunately, most animals, especially dogs and cats, after a small taste, will avoid eating most dangerous plants. However, we animal lovers know that some dogs will eat anything and even some cats are less than discerning.

Many plants contain toxic substances. On their website, the ASPCA Animal Poison Control Center lists well over 300 potentially toxic plants. I was very surprised to find the names of plants that I recognized and didn’t know were potentially dangerous, while others I knew to advise animal owners to avoid.

There are so many potentially poisonous plants I cannot possibly mention all of them in one column, so I have decided to do a series. First, let’s talk about those plants that contain insoluble calcium oxalates. Most of the plants that accumulate calcium oxalate accumulate the insoluble form of the compound. Ingestion of these plants results in irritation of the mucous membranes of the mouth, tongue and lips accompanied by an intense burning sensation. Animals afflicted usually drool excessively and may vomit and have difficulty swallowing.

Most of the Philodendrons accumulate these oxalate crystals including; the Saddle Leaf Philodendron, also known as Horsehead, Cordatum, Heartleaf, Panda Plant, Split Leaf, Fruit Salad Plant, Red Emerald, Red Princess and Fiddle Leaf and the Cut leaf Philodendron also called the Hurricane Plant, Swiss Cheese Plant, Ceriman, Mexican Breadfruit and Window Leaf Plant.
Various Dieffenbachia, contain insoluble calcium oxalates. These include; the Charming Dieffenbachia, Dumb Cane, Giant Dumb Cane, Spotted Dumb Cane, Tropic Snow, Exotica, Exotica Perfection, and the Gold Dieffenbachia.

Many of us have Schefflera growing in our homes. My wife has been nurturing one, and its offspring, for more than 30 years. The Schefflera (Umbrella Tree, Australian Ivy Palm), the Octopus Tree and the Star Leaf all contain insoluble calcium oxalates.

A host of plants, all classified in the Araceae family, harbor these substances. These include; the Flamingo flower also known as; Devil’s Ivy, Pothos, Golden Pothos, Taro Vine, Ivy Arum, Marble Queen. Other Araceae are the Caladium, also known as; Elephant Ears, Malanga, Stoplight, Seagull, Mother-in-law Plant, Pink Cloud, Texas Wonder, Angel-Wings, Exposition, Candidum, Fancy-leaved Caladium, and Alocasia. The Flamingo Lily (Tail Flower, Oilcloth Flower, Pigtail Plant, Painter’s Pallet) and various species of Calla including; Calla Lily, Pig Lily, White Arum, Trumpet Lily, Arum Lily, Garden Calla, Black Calla, Solomon’s Lily, Wild Calla, Wild Arum, and the Mauna Loa Peace Lily. This family also includes the Nephthytis (Arrow-Head Vine, Green Gold Nephthytis, African Evergreen and Trileaf Wonder). Arums including; Lord-and-Ladies, Wake Robin, Starch Root, Bobbins and Cuckoo Plant accumulate oxalates.

On some of our area hikes, my now 10-year old granddaughter has shown me Skunk Cabbage (also known as Skunk Weed, Polecat Weed, Meadow Cabbage, Swamp Cabbage). The Chinese Evergreen has insoluble oxalate crystals as do the Greater Ammi (Bishop’s Weed, False Queen Anne’s Lace). Finally, there are over 1,000 species and 10,000 hybrid Begonias that can accumulate these crystals — ouch!

It doesn’t end there. Some plants contain soluble rather than insoluble calcium oxalates. Ingestion of these plants can result in excessive salivation, tremors and even kidney failure. Plants with the soluble calcium oxalates found in their leaves include; Rhubarb (Pie Plant), Sorrel (Dock) and Moss Rose (Wild Portulaca, Rock Moss, Purslane, Pigweed, Pusley). Don’t let your pet munch on the leaves of these plants.

If you believe your pet has been grazing on any of the plants described, please take the animal to your veterinarian and bring along a sample of the plant for identification.

I’m far from done. In follow-up columns, I will let you know about plants that contain saponins, alkaloids, glycosides, volatile oils, deadly ricin, and at least 30 other toxic substances. It’s a scary world we live in, and it’s not just the politicians.

Dr. David Gross of Edmonds graduated from Colorado State University’s veterinary school in 1960 and was in private practice for 10 years. He retired in 2006 as Professor and Head of Veterinary Biosciences, at the University of Illinois, Urbana-Champaign.

Leave a Reply

Your email address will not be published. Required fields are marked *

Real first and last names — as well as city of residence — are required for all commenters.
This is so we can verify your identity before approving your comment.

By commenting here you agree to abide by our Code of Conduct. Please read our code at the bottom of this page before commenting.