A surprising number of the plants in our gardens may be toxic or irritating to our pets. While you might not consider eating most of these, pet owners know animals are sometimes less discriminating about what they chew. Here are some plants to keep away from dogs and cats.
The first red flag is cycads. Sago palm, which is actually a cycad and not a palm, may be one you encounter. Sago is a starchy product derived from the pith of cycads and palms, and is highly processed to make it edible. An infamous example is the arrowroot starch derived from the native coontie, later banned by the U.S. Food and Drug Administration. However, all cycads contain at least three toxins affecting animals, including people. No part of any cycad is safe to consume.
Another big category to keep your pets from gnawing is aroids (aka arums), the group of plants including philodendrons, pothos, peace lily (Spathiphyllum), arrowhead plants (Syngonium), elephant ear (Caladium), Dieffenbachia and others. These contain crystals of calcium carbonate called raphides, which take the form of microscopic needles. Obviously, these can cause discomfort and irritation to the mouth, lips and throat, but usually no more than that unless a huge quantity is consumed.
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The ASPCA list of toxic plants includes the very common Lantana camara. This is all over South Florida. We'll never understand why a dog or cat might think to eat it, but keep them away from it. The ASPCA also lists the ti plant (Cordyline terminalis), another widely used landscaping plant, which tends to be too tall for a pet to reach.
Surprisingly, the ASPCA indicates poison ivy as non-toxic to cats, dogs, and horses, though if they get it on their fur, they can spread urushiol, the compound that causes skin irritation familiar to all who have wandered too close to poison ivy.
While the level of toxicity of poinsettia might be debated, it is still not something for pets to eat. The poinsettia’s family, the euphorbias, exude an irritating latex-like fluid. Other common euphorbias include crotons, crown of thorns, and many other cactus-like plants.
It’s fascinating that animals like dogs, cats, and horses are affected by plants so differently than people are. For example, aloe is considered toxic to these animals, but is used in some forms by people who consider it a health aid. Tomatoes too are toxic, except for the ripe fruit. Tomatoes are members of the same family as nightshade, tobacco and Brunfelsia. And though you won’t find them in South Florida gardens, apples are a “no” for cats and dogs.
It's less surprising that these plants make the dangerous list: castor bean (Ricinus communis), actually common in landscaping; and rosary pea (Abrus precatorius), a nasty invasive. Both can be fatally toxic.
Asclepias species, aka milkweed, are also toxic to animals. However feeding on it as caterpillars gives monarch butterflies their unpalatability to predators. Atala butterflies use a similar strategy based on their coontie consumption.
I am certainly not a veterinarian or expert in this field; these are just some of the plants you may commonly encounter that may be a health threat to your pet. Symptoms related to plant poisoning are numerous and vague, and are best left for the experts. As always, if your pet is acting strangely or seems sick, call the veterinarian.
The best strategy is to keep pets away from plants in the first place. Otherwise, place barriers around potentially toxic plants. Dogs can be blocked, but cats are not easily deterred; they should be kept inside anyway. Outdoor cats cause damage and kill wildlife, and themselves suffer from fleas, animal attacks and cars.
I encourage you to research this topic for yourself. Once you start reading, it’s an eye-opener to realize how many plants can be toxic or irritating depending on what part of the plant is eaten, or if it’s in excessive amounts, or raw versus uncooked.
Check out further reading at The University of Florida at http://sfyl.ifas.ufl.edu/agriculture/toxic-plants/ or search for toxic plants at https://www.aspca.org. In an emergency, call a veterinarian or the Animal Poison Control Center 24-hour emergency hotline at 888-426-4435.