9 Surprising Finds in the Poisonous Plant Garden

Aug 3, 2015 / Emergency/Critical Care / Preventive Health / Cats / Dogs / Horses

[oleander in the University of Illinois Poisonous Plant Garden]

The poisonous plant garden is educational for students, veterinarians, and pet owners

With over 400,000 plant species on our earth, it’s easy to forget that each individual species has its own characteristics, just like animals do. In what we perceive as pleasant green surroundings, there may lurk deadly toxins for animals and people.

Fortunately, pet owners can unmask these dangers at the University of Illinois College of Veterinary Medicine poisonous plant garden.

“The garden allows veterinary students to become familiar with plants that might pose a threat to their future patients,” explains Lynsee Melchi, a third-year veterinary student and the senior student curator of the garden.

“Working in the garden has taught me what plants are available to what animals in each season. Once you become familiar with them, poisonous plants will catch your eye wherever you go.”

Garden-Variety Threats

Would you believe that tomatoes, kale, and cabbage have a place in our poisonous plant garden? You can safely eat them, but know the risks.

Tomatoes are not poisonous when they are ripe, but the green ones as well as the leaves and stems contain solanine, a compound that primarily causes excess salivation and adverse gastrointestinal effects.

“Kale, cabbage, and other Brassica plants contain substances that sequester iodine in the body and could contain nitrates if the plant gets stressed, for example with drought,” says Melchi. “Iodine is important for thyroid function. An individual who is hypothyroid might run into trouble if they have a kale smoothie for breakfast and lunch.”

Famous Killers

Have you ever noticed wide swatches of large plants with white flowers commonly found on hillsides in June? You are probably looking at a big patch of poison hemlock, the plant used in the poison Socrates drank when he was put to death in ancient Athens.

“White snakeroot, which allegedly caused the death of Abraham Lincoln’s mother, is harmful to all animals that consume it, especially horses. In horses it primarily produces degeneration of the heart, while in other species it may cause neurological signs,” says Melchi. “The toxin tremetol is heavily excreted in the milk of animals that eat white snakeroot, thereby potentially poisoning their offspring or any humans consuming that milk.”

Useful, Beautiful, and Toxic

Some poisonous plants have useful characteristics—as long as you don’t eat them.

“Communities of old washed their dishes using Bouncing Bet, which contains soap-like compounds, and Scouring Rush, which contains silica,” says Melchi.

Many garden beauties are also poisonous.

“Oleander contains a potent cardiotoxin. It takes very few leaves to kill an individual. In the Southern and West Coast states, it is a very common plant,” warns Melchi. (Oleander is the red flower in the photo above.)

“Day lilies, along with Easter lilies and tiger lilies, can cause kidney degeneration and failure in cats very quickly, which will be fatal without immediate veterinary care.”

There are many more plants to learn about in the poisonous plant garden, which serves as an important educational tool for students, veterinarians, and pet owners.

Anyone interested in a tour should contact Dr. Michael Biehl, clinical professor of biosciences, at biehlml@illinois.edu or plan to visit during the annual Champaign County Master Gardeners Garden Walk every June, when tour guides are available all day.

Can’t wait that long? There is information online about the plants in the garden at vetmed.illinois.edu/poisonplants.

By Melissa Giese