Poisonous Plants Dos and Don'ts

Although the below-ground portion of the potato is perfectly edible, the above-ground portions are poisonous to humans. All species of delphinium, a common perennial in much of the country, are considered toxic, especially the young leaves and seeds. Ingestion of any part of the plant may cause nervous symptoms, nausea, depression, even death. Fava beans, common in southern gardens, are toxic to people with an inherited red blood cell enzyme deficiency. Within 24 hours after eating the beans, such symptoms as headache, dizziness, fever and vomiting may appear. The leaves and unripe fruit of lantana, common in many parts of the country, have been linked to accidental poisonings in children, and contact with the leaves can cause dermatitis. Caladiums (left) and the related houseplant dieffenbachia, or dumb cane, produce compounds that, when ingested, cause intense burning, swelling and irritation of the mouth, lips and throat. Poinsettias aren't the menace they were once thought to be.

Many commonly grown plants are actually poisonous. It may be only the leaves that are poisonous, or only the roots or stems or berries. Often, however, the whole plant is poisonous, including the nectar and pollen, and it may be deadly. But it depends who's eating them. Although many insects and animals can eat plants without any ill effects, that doesn't mean the plants are safe for human consumption. For instance, squirrels are notorious for eating daffodil bulbs, and the toxic alkaloids don't seem to bother them at all, but the bulbs and leaves can cause diarrhea, vomiting, sweating or death in humans if ingested. Here are just a few other familiar plants that have been associated with accidental poisonings:

• The widely cultivated and extremely popular groundcover lily-of-the-valley is one of the most poisonous of all landscape plants. Ingestion of any part can quickly lead to coma and death.
• The autumn crocus, the species from which we get the wonderfully aromatic spice saffron, is extremely poisonous, and symptoms are said to mimic those of arsenic poisoning. But don't worry, the saffron itself is perfectly safe.
• Foxglove, an old-fashioned favorite, is the source of digitalis, a potent heart medication. Eating any part of this plant can cause all sorts of problems, including death.
• All 48 species of lobelia are believed to be poisonous, especially the leaves and seeds, and there are reports of human fatalities associated with several of them.
• Castor beans are gaining again in popularity, and they do make terrific annual shrubs; however, just one seed contains enough toxin to kill an adult.
• A number of landscape shrubs are poisonous, including many of the most popular such as boxwood, rhododendron (including azaleas), laurel, daphne, yaupon holly and oleander. One of the most poisonous of the lot is the enormously popular yew, which contains several potentially fatal toxins, many of which are showing promise as anticancer drugs.
• Among vines, there are several deadly selections, including wisteria, various ivies, Virginia creeper and trumpet vine. Of course, no list of poisonous plants would be complete without poison ivy, poison oak and poison sumac, all of which are notorious for producing severe skin rashes. And there are numerous other poisonous plants, like deadly hemlock (the perennial weed, not the tree), henbane, buttercups, milkweed, nearly all lupines and the leafy portions of tomatoes and rhubarb.
• Is the poinsettia one of the bad guys in plants? Contrary to common belief, no part of these holiday beauties is toxic to either people or pets. The myth began in 1919 when a doctor erroneously listed the poinsettia as the cause of death in a toddler. Since then, numerous health agencies and scientific researchers have tested the leaves, bracts, stems and sap of the plant. The conclusion: poinsettias are not poisonous. But that doesn't mean anyone would want to eat them. The poinsettia tastes extremely bitter and ingestion could cause stomach discomfort and vomiting. And the milky sap can trigger allergic reactions and skin irritations.

Dos and Don'ts About Poisonous Plants

Thousands of people are poisoned each year by ingesting seemingly harmless plants; half of those affected are children. Remember to call your local Poison Control Center if you have any questions regarding poisonous plants in your home or landscape. Here are some other tips to help prevent and treat illness from poisonous plants:

• Teach children never to eat leaves, stems, bark, seeds, mushrooms, nuts or berries from outside.
• Keep plants that you know to be poisonous out of reach of children. Store bulbs and seeds out of sight and out of reach.
• As much as possible, know the names of all plants in your house and yard. If you don't know the name of a plant, have it identified at your local nursery or home-and -garden center.
• If you take someone to the doctor or emergency room because he or she has eaten a plant, take a sample of the plant with you for identification.
• Any plant that has been treated recently with insecticides or other chemicals should be considered poisonous until proven otherwise.
• Don't assume a plant is safe because birds or other wildlife will eat it.