Spring isn’t the only time pet owners need to worry about hazards in the garden and toxic plants — fall can be just as dangerous. As a veterinary toxicologist for the ASPCA Animal Poison Control Center, I know we’ll be receiving calls this season about pets ingesting poisonous plants, seeds and fungi — many of which can be found in your own backyard.
The toxic edibles in your garden, yard or home can cause anything from stomach upset to sudden death, so it’s important to know which plants are dangerous for pets. If you suspect your dog or cat has consumed one of these poisonous items, contact your veterinarian immediately.
Plant and Garden Hazards to Avoid This Fall

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Mushrooms
They may be pretty, but wild mushrooms can be deadly for pets. Dogs are most susceptible to accidentally ingesting mushrooms when they scavenge in the yard or during walks. Since many mushroom species prefer humidity to the dry heat of summer, they typically become more common in fall's cool, moist conditions. Identifying mushrooms can be very difficult, so if your pet ingests one, contact your veterinarian immediately and try to take a sample of the suspected mushroom. Depending on the mushroom species, affected dogs may begin to vomit within 15 minutes to several hours after ingestion. Vomiting can last a few hours to a couple days.

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Black Walnuts
Black walnuts are not known to be toxic, by themselves, to dogs. But the nuts can become poisonous when they fall from trees and grow molds, which can cause tremors and seizures if ingested.

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Acorns
Acorns contain a toxin called Gallotannin. Dogs usually do not ingest heavy quantities of acorns, but if they do consume a few that dropped to the ground, they may have mild to moderate gastrointestinal upset. Acorns can also become lodged in the GI tract and cause an obstruction.

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Leaf Piles
The leaves, bark and twigs of many trees, such as oak, red maple, cherry and apple, can be irritating and even toxic to pets if consumed. Running through leaf piles might be fun, but make sure your pet isn't doing any snacking while playing.

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Autumn Crocus
Autumn crocus (Colchicum autumnale) contains chemotherapy-like compounds that attack rapidly dividing cells in the body. Ingestion can cause vomiting, diarrhea, weakness and possible death. Do not confuse this flower with the innocuous spring crocus (Crocus spp.), which is not toxic.

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Lilies
A bouquet of lilies might seem like a nice gift for the upcoming holiday season, but members of the true lily family (Lilium and Hemerocallis) have been shown to cause kidney failure in cats. Some examples of true lilies include Easter lilies (L. longiflorum), tiger lilies (L. tigrinum), rubrum or Japanese showy lilies (L. speciosum, L. lancifolium) and day lilies (H. species).
Even a small amount of exposure (a few bites on a leaf, ingestion of
pollen, etc.) may result in kidney failure. Cats often vomit within a
few hours of exposure and may stop producing urine within 72 hours. Cats who
receive quick treatment (including intravenous fluids) should have a good
prognosis.

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Yews
Yews are commonly used as landscaping plants, since they stay green
year-round. A pet looking for something green to nibble on may be tempted to take a bite. But yews contain compounds that can cause an irregular heartbeat or even stop the
heart. Sudden death can occur within hours of
ingestion.
More on Vetstreet:
- 5 Pet Dangers to Avoid This Fall
- Is It Safe for Pets to Lick Lotion?
- A Warning to Pet Owners Who Use E-Cigarettes
- 5 Common Mushrooms That Can Poison Your Pet
- Why Laundry Detergent Pods Are Dangerous for Pets