A Popular Flowering Garden Shrub Is Toxic To Your Dog

If there's one behavioral no-no you can usually bank on with dogs, it's that they'll eventually chew on something they shouldn't, especially if they're young. Some chew holes through socks, while others shred sofa cushions or leather shoes. Other dogs prefer to eat plants, both in the house and outdoors, but this can be a bad idea due to the toxicity risk of many species. One plant, in particular, that should be kept away from dogs is a popular garden shrub: hydrangeas.

Known for their large, showy flower clusters and color varieties, hydrangeas adorn many front porches, yards, and gardens. They're hard to miss, especially if they're blue or purple, and although animals don't see the same way humans do, these shrubs could get the attention of canines, too. Unfortunately, though, despite their alluring appearance, hydrangeas can be harmful to dogs if ingested due to a toxin in them called amygdalin.

Every part of the hydrangea plant is toxic to dogs, but the leaves and flowers are the most dangerous because they contain the highest amount of amygdalin. When this toxin is ingested by a dog, it metabolizes in the body until it produces cyanide, a poisonous chemical compound that can make your canine companion ill.

Many plants, foods, and other substances pose a toxicity threat to dogs, but "toxic" doesn't always equate to "deadly." In fact, hydrangeas are only mildly toxic, and the risk depends on the amount consumed and the size of the dog. This means a small dog that weighs under 10 pounds that chomps down on a few petals could experience symptoms, while a 120-pound dog that eats the same amount might exhibit none. The good news is that dogs getting cyanide poisoning from hydrangea ingestion isn't common at all — in fact, it's so rare that the actual amount required to generally cause acute toxicity symptoms in canines hasn't been determined.

If your dog were to consume enough hydrangea to show symptoms, it might experience vomiting, diarrhea, lethargy, and stomach pain. You may also notice a loss of appetite or depression. If the amount of hydrangea ingestion is large enough to lead to cyanide poisoning, the symptoms can manifest within 20 minutes and include rapid breathing, muscle spasms, an increased heart rate, excitement, and fever, among others.

With these risks in mind, avoid planting hydrangeas in any portion of your yard that your dog uses, create a barrier in front of the flowers, or just keep an eye on your pet. You could also consider planting flowers that won't harm your dog. 

If you believe your pet has consumed a toxic substance and you can't reach your veterinarian or an emergency clinic, please contact the ASPCA 24/7 Poison Control Hotline at 888-426-4435 or the Pet Poison Helpline at 855-764-7661.