Learning From Poisonous Plants

  • Relf, Diane

We live in a time of environmental crisis when all plant life should be promoted and valued, rather than feared for any potential poisonous qualities. Plants are extremely diverse organisms, however, and should be respected for their ability to poison as well as feed humans.

There is no set manner by which plants poison. Most plants must be ingested to become toxic, while others can be touched (in the case of dermal reactions). Toxicity depends on the amount of plant material ingested. For example, all parts of the sunflower Helianthus annuus fall on the "slightly toxic" plant list. Since sunflowers are a large part of our snack food diet, this comes as a surprise, but is a perfect example of toxicity as a function of ingested amount. But doesn't ice cream make us sick if consumed in disproportionate amounts? So, should we fear all plants in the landscape and keep our children locked in boxes so no one risks their lives around plants? Certainly not!

Just because a plant produces poisonous berries or leaves does not automatically exclude it from use in a home landscape. In PLANTS FOR PLAY (MIG Communications), Robin C. Moore says that the great majority of our landscape plants are "highly beneficial and perfectly safe" for children, but there are many plants containing poisonous substances that warrant precaution. Adults should learn about their landscapes and be able to distinguish those plants that are potentially hazardous. In turn, adults should caution their children about those plants and plant parts that carry toxins.

There is no need to alienate children from plants, making them afraid of plant life. Instead, there is a great need to change the child's perspective to that of respect for all plant life, so the child has less risk of exposure to dangers. The education process provides a great opportunity for parent and child to share and grow in enjoyment of the environment.

The age of the children playing in the yard is a major consideration when planning your landscape. Berries produced on plants at perfect heights for small children, such as the poisonous fall berries of Convallaria majalis (Lily-of-the-Valley), are at ground level and much more of a concern for toddlers or small children than ten-year-olds.

Recent trends in home landscaping involve a strong wildlife interest as a major factor in plant selection. Homeowners are asking for plants that produce berries that persist to feed birds, squirrels, chipmunks, and other wildlife creatures. These berries not only appeal to wildlife, but appeal to small children as well. Patterning after parents picking blackberries, strawberries, and other edible fruits may encourage a child to pick and eat these tempting, poisonous berries. The best way to protect small children from plant poisoning is to teach them to not eat any plant parts without adult supervision until they are old enough to be positive that the plant is safe to eat.

We cannot ignore plants -- the hand that feeds us, so-to-speak. Human and animal life cannot exist apart from green flora, so we must learn how to live with it. This means plant education for all people, big and small.

Some Common Landscape Plants and Their Toxic Parts

    Yew Taxus seeds
    Privet Ligustrum leaves and berries
    Sunflower Helianthus annuus all parts, if ingested in excess
    Burning Bush Euonymous berries
    Jack-in-the-Pulpit Arisaema triphyllum fruits
    Bittersweet Celastrus orbiculata, C. scandens fruits
    Daphne Daphne mezereum berries
    Pokeberry Phytolacca americana berries
    Chokecherry Prunus virginiana seeds
    Black Nightshade Solanum nigrum berries
    May Apple Podophyllum peltatum fruit
    Poison Ivy Rhus radicans berries
    Oleander Nerium oleander all parts
    Rhododendron, Azalea Rhododendron spp. leaves
    Castor Bean Plant Ricinus communis seeds

Diane Relf, Extension Specialist, Environmental Horticulture

(Originally published as "Learning from Poisonous Plants," by Diane Relf, Extension Specialist, Consumer Horticulture, and Sheri Dorn, Horticulture Extension Technician, Virginia Tech, in The Virginia Gardener Newsletter, Volume 13, Number 8.)

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