What Outdoor Plants Are Poisonous to Pets?

A number of common house and garden plants can be toxic to cats and dogs. When possible, keep poisonous plants out of reach of your pets. If you are unable to move or erect a barrier around the plants, and you see your pet eating any of them, watch carefully for adverse symptoms. Because not all pets may exhibit symptoms, consider taking your pet to the vet to check for poisoning even if it appears healthy.


Aloe is a perennial succulent that can grow to 4 feet tall. It is comprised of fleshy, liquid filled spear-like leaves. Aloe is poisonous to both cats and dogs. It can cause vomiting, depression, anorexia, tremors and changes in urine color in small animals. If you have seen your cat or dog eating aloe and see any of these symptoms, take your pet in for medical care as soon as possible.

American Bittersweet

American bittersweet is a hardy ornamental vine that grows in many parts of the United States. It can grow vigorously and become invasive. Its leaves are 2 to 4 inches long and about 1 to 2 inches wide. The vines produce small greenish-yellow or greenish white flowers in June. The flowers turn to a round orange-yellow capsule that bursts in autumn to release scarlet red seeds. American bittersweet is toxic to cats, dogs, and horses. Symptoms of animal poisoning include weakness and convulsions, along with vomiting and diarrhea.

American Mandrake

American mandrake, sometimes called "mayapple," is a perennial plant that is native to the eastern United States. American mandrake grows 10 to 15 inches tall with 6 to 10 inch long leaves with deep lobes. All parts of this plant are poisonous to all animals, including cats, dogs and horses. The toxicity of the plant will depend on how much of the plant your pet has eaten. Symptoms of poisoning can include skin redness, skin ulcers, vomiting, diarrhea, panting and loss of energy or lethargy. In some cases, if your pet has eaten enough American mandrake, it may result in a coma. Because this plant is so toxic, if you observe your pet eating it, seek veterinary care as soon as possible.

Keywords: poisonous plants, plants poisonous to pets, pet poisoning

About this Author

Christopher Earle is a freelance writer based in Denver, Colo. He has been writing since 1987 and has written for National Public Radio, the Associated Press, the Boeing Company, Ford New Holland, Microsoft, Active Voice, RAHCO International and Umax Data Systems. He studied creative writing at Mankato State University in Minnesota.