5 Common Plants You Might Not Realize Are Poisonous

There are many plants we've all been warned to avoid, like poison ivy, castor bean and Datura, which can be unpleasant, and even deadly, when ingested. Then there are some plants, like poinsettia, which have gotten reputations worse than they deserve. But there are also many commonly grown garden and house plants that can cause poisoning problems for humans, ranging from itching to death, yet few people know to be cautious around them.

While most of us know not to taste test plants just because they look or smell luscious, we need to use extreme caution when gardening with small children and pets around. Don't assume that just because a plant is commonly grown, that it is harmless. There are more sources, listing which plants are poisonous and what problems they cause, listed at the bottom of the article.

Here are five common plants you may never have considered as poisonous or dangerous.

  • 01 of 05

    Chinese Lantern Plant

    Chinese lantern plant with red seed pods

    The Spruce / K. Dave

    You might grow Chinese Lantern for the colorful, fun, seed pods and the papery sheathe that slowly exposes them. The seed pods dry well and are popular in flower arrangements. The ripened fruits are sometimes used to make jams and jellies but don't attempt this unless you know what you are doing. The unripe berries can be highly toxic and possibly fatal.

    • Poisonous parts: Unripe berries, leaves
    • Symptoms: Headache, stomachache, vomiting, diarrhea, low temperature, dilated pupils, breathing problems and numbness
  • 02 of 05


    A close-up of hardy fall mums

    The Spruce / Marie Iannotti

    What would fall be without mums? For the most part, mums are not dangerous. However, those garden mums we see on every garden shelf in fall can be a severe skin irritant, for some people. If you haven't had problems handling mums before, perhaps you're not susceptible. But it's good to know the signs to watch out for before the problem gets out of hand.

    • Poisonous parts: Leaves, flowers
    • Symptoms: Skin reddening, scaling, blisters
  • 03 of 05


    Hydrangea with white flowers

    The Spruce / K. Dave

    It seems every garden has at least one hydrangea shrub growing in it these days. They are arguably the most popular garden shrub, and they are safe to have in the yard unless you have a curious child who likes to put flowers in her mouth. Humans should avoid them for several reasons including stomach upset, skin irritation and, in severe cases, more serious problems like convulsions and coma. Unfortunately, rabbits will be perfectly happy (and healthy) munching on your hydrangeas, as they like to do in winter.

    • Poisonous parts: Leaves, flowers, bark
    • Symptoms: Stomach pain, nausea, vomiting, and sweating
  • 04 of 05


    A close-up of lantana (shrub verbena)

    The Spruce / Marie Iannotti

    Lantana has become a garden staple, whether it is grown as a perennial, in warm climates, or as annual plants in areas with cold winters. As a skin irritant, it only causes mild and short-term irritation, so you might not even have noticed that it bothered you. However, if the berries are ingested, it is highly toxic and possibly fatal. You might not be tempted, but watch for kids and pets.

    • Poisonous parts: Green, unripened berries, leaves (skin irritant)
    • Symptoms: Vomiting, diarrhea, dilated pupils, trouble breathing
    Continue to 5 of 5 below.
  • 05 of 05

    Rhododendron and Azalea

    Rhododendron with fuchsia flowers

    The Spruce / K. Dave

    Many homes are encircled with these flowering shrubs, and you wouldn't expect them to be poisonous, the way the deer devour them. The deer might love them, but for mere mortals, all parts of Rhododendron and Azalea plants are extremely toxic if ingested and may be fatal. Don't take any chances with these. If someone ingests any part of the plant, seek medical help immediately.

    • Poisonous parts: All
    • Symptoms: Burning in the mouth, salivation, watery eyes and nose, vomiting, diarrhea, nausea, difficulty breathing, weakness, abdominal pain and progressive paralysis of arms and legs. Ingesting rhododendron can affect your heartbeat and cause convulsions and coma
Article Sources
The Spruce uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Guide to Poisonous Plants. Colorado State University

  2. Bleumink, Eric, Mitchell, John C, Nater, Johan P. Contact Dermatitis to Chrysanthemums. Journal of the American Medical Association Dermatology, 108,2,220-222, 1973, doi:10.1001/archderm.1973.01620230020007

  3. Poisonous Plants. Michigan State University Extension.

  4. Jansen, Suze A et al. Grayanotoxin Poisoning: 'Mad Honey Disease' and Beyond. Cardiovascular Toxicology ,12,3,208-215,2012, doi:10.1007/s12012-012-9162-2