The ASPCA lists garden and indoor plants that can cause medical difficulties for your pets, as well as plants that are outright toxic (such as daylilies and morning glories). Pets that have allergies or other sensitivity may react to plants that are not listed here. This is not a definitive list but some of the most serious plants are listed below.
Plants that are dangerous for dogs can produce symptoms that include stomach distress, vomiting, panting, inability to remain conscious, organ damage, even death. If you suspect poisoning, take your dog to a vet.
The oleander (Nerium oleander) is a fragrant evergreen that is fast-growing. It is a member of the dogbane family. This shrub gets up to 20 feet tall and 10 feet wide. Flowers are in white, pink, yellow, salmon and red. Bright green leaves are 4 to 10 inches long and lance-shaped. Typically it is used for hedges, beach plantings, and formed to a small tree. The plant is toxic and should not be ingested. Don't breathe the smoke of this plant, if burned. It can also cause skin irritation and inflammation. Pets and children should avoid this shrub.
Yesterday Today and Tomorrow
The "Yesterday Today and Tomorrow" plant (Brunfelsia pauciflora) is an evergreen from the nightshade family. Flowers are pans-like and start out purple, going to lavender, and then ending white. Blooming occurs from spring to summer's end. Leaves are 3 to 6 inches long, dark green, and leathery. It is typically used in containers or as a mixed hedge. Berries are very toxic and the plant has poisonous alkaloids. Keep away from dogs, as well as all pets, and children.
The windowleaf, Monstera deliciosa, is an evergreen perennial from the arum family. Vines can get up to 70 feet long, with large glossy leaves, tiny flowers and fruits that are fragrant and look like green corn on the cob. It is typically used as a houseplant, a pergola plant, or seen on palm trees. Windowleaf is poisonous, containing oxalic acid, everywhere but the fruits. It can be a skin irritant as well.
The Natal plum, Carissa macrocarpa, is a fragrant evergreen that is part of the dogbane family. It is drought-tolerant. It can get up to 20 feet tall with dark green leaves 1 to 3 inches long with white star-like flowers. Fruits are red berries, 2 inches long, and taste like a sweet form of cranberry. The plant is typically seen as a screen or hedge plant. Everything on the natal plum but the fruit is poisonous, including the seeds of the fruit. Sharp spines on it can also injure your dog--as well as you.