Heres a resource for learning about poisonous plants for cats, dogs and humans. Tiger lilies are among the worst poisonous plants for cats and jasmine for dogs, while castor bean is the source of toxic ricin and is a poor choice to grow if you have kids. Most of these resources focus on plants poisonous to humans; the bottom 2 resources pertain to pets.

Address: 249 West 17th Street, New York, NY 10011
Website: http://landscaping.about.com/od/poisonouslandscapeplants/Poisonous_Plants_for_Cats_Dogs_Humans.htm