Veterinarians receive many calls asking whether certain plants are poisonous to their pets. Fortunately, actual poisonings are quite rare. Some plants have to be eaten in large volume to produce signs, while one berry or seed from other plants may be fatal. The following are potentially toxic; most will merely cause nausea and regurgitation. If any symptoms develop, call your vet.
Plants affecting the gastrointestinal tract (symptoms may include loss of appetite, vomiting and diarrhea): azalea and rhododendron (a great quantity of leaves must be ingested); bulbs, corms or root stalks of tulip, daffodil, naked lady, iris and amaryllis; hulls of English and black walnut (may also produce convulsions). Deaths have been reported from the following: berries of mistletoe; fruit and foliage of English ivy; seeds of castor bean and rosary pea.
Ingestion of any species of solanum--leaves and fruit of black nightshade, berries of Jerusalem cherry, climbing nightshade--may in addition cause paralysis and unconsciousness.
Plants causing inflammation of the mouth (symptoms include irritation in the mouth, head shaking, thirst, salivation and swelling in the throat): dumb cane, philodendron, elephant's ear, calla lily, caladium.