The following list includes only a few landscape plants known to be toxic to household pets. If you observe erratic behavior in your pet after ingesting any plant, contact your veterinarian immediately.
Toxic plants: 

Amaryllis,	Angel’s Trumpet	Antherium	Asparagus Fern	Azalea,	Boston Ivy
Calla Lily	Caladium	Castor Bean	Chrysanthemum	Croton	Crown of thorns
Cuban Laurel	Dieffenbachia,	Dracaena,	Philodendron,	Golden Pothos	Hydrangea
Japanese Yew	Jatropha	Lantana	Milkweed,	Oaks	Oleander
Pencil Cactus	Periwinkle,	Rosemary	Schefflera	Snapdragon	Peace Lily
		Wandering Jew	Yellow Jasmine

Additional Resource
http://www.aspca.org/site/PageServer?pagename=pro_apcc_toxicplants#A