Are Hydrangeas Poisonous to Cats? hydrangeas cats Guide

Are Hydrangeas Poisonous to Cats?

Keep your curious kitten away from hydrangeas, no matter how gorgeous they appear in your garden or as a bouquet.

What are Hydrangeas?

Hydrangeas are beautiful flowering plants known for their large, colorful blooms. They come in various colors, including blue, pink, purple, and white, making them a popular choice for gardeners and floral arrangements alike. However, beneath their stunning appearance lies a potential danger for our feline friends.

Hydrangeas are renowned for their lovely blossoms, but if cats chew on any portion of the plant, they might become ill. While certain hydrangea kinds are more poisonous than others, all are capable of poisoning cats. Here’s how to keep your cat safe and secure.

Not every plant is suitable for feline ingestion, whether you have an adventurous cat who roams the wilds of your garden or an inquisitive kitten on the countertop. While many plants are healthy for cats, many others are not.

Are Hydrangeas Harmful to Cats?

To put it bluntly, no. You must keep a close eye on your cat if you want to grow flowering hydrangeas in your garden. Amygdalin is found in the flowers, leaves, buds, and stalks, although the concentration is greater in the buds and young leaves. Cats feel ill when they consume any part of the hydrangea plant.

Why Are Hydrangeas Poisonous to Cats?

Are hydrangea poisonous to cats? Cyanogenic glycosides, which are found in hydrangeas, are harmful to cats and other animals (including humans). The chemical is produced when the plant is chewed or consumed, and it can induce a range of symptoms such as vomiting, diarrhea, and lethargy.

Cyanogenic glycosides are compounds that can emit cyanide when they come into contact with specific digestive enzymes. While the level of toxicity varies based on the species of hydrangea and the amount consumed, it’s crucial to remember that any amount of cyanide can be harmful to cats.

Are Hydrangeas Poisonous to Cats?

There are approximately 75 different species of hydrangeas, and all of them contain chemicals that can be toxic to cats if consumed in significant numbers. The most deadly hydrangea to cats, however, is the Bigleaf hydrangea (Hydrangea macrophylla). This plant contains a chemical that, if taken in excessive quantities, can induce vomiting, diarrhea, and lethargy in cats. Bigleaf hydrangea blooms have a greater quantity of the toxin than the leaves or stems.

While certain hydrangeas are more poisonous than others, any plant may be harmful to cats if consumed in sufficient quantities. If you believe your cat has eaten any part of a hydrangea or any plant, seek veterinarian care right away.

Common Symptoms of Hydrangea Poisoning in Cats

If your cat has ingested hydrangeas, you may notice the following symptoms:

  • Vomiting and Diarrhea

One of the initial signs of hydrangea poisoning is vomiting and diarrhea. If you observe these symptoms in your cat and suspect hydrangea ingestion, seek immediate veterinary care.

  • Lethargy and Weakness

Cats affected by hydrangea poisoning may display lethargy and weakness. They might appear less active and have difficulty moving around.

  • Drooling and Excessive Salivation

Excessive drooling and salivation are common signs of plant poisoning in cats. If you notice your cat drooling excessively, it could be an indication of hydrangea toxicity.

  • Loss of Appetite

Hydrangea poisoning can lead to a loss of appetite in cats. If your cat suddenly shows disinterest in food, it’s crucial to consider potential poisoning.

How to Prevent Hydrangea Poisoning

Because hydrangeas are poisonous for dogs, too, take good care of your animal friends by changing the dynamics of your landscape.

If you already have hydrangeas in your yard, make it more difficult for cats to get to them. “Place shells, branches, and thorny vines that are unappealing for a dog or cat to step on,” advises Burch.

She also suggests using non-toxic botanical oil sprays around the perimeter of the plants, since these products have a strong odor that animals dislike. Cats dislike citrus, so mix grapefruit, lemon, lime, or orange juice in water for a quick and simple spray, or try a commercial solution like Four Paws Bitter Lime Deterrent Spray. Motion-activated sprinklers and ultrasonic deterrents can also be useful.

The most effective hydrangea poison protection, however, is to keep cats indoors (which is better for their general health) or in a cation. Unless you want to train them to walk on a leash and harness for (supervised) exploration!

Here are some tips to help keep your cat safe from hydrangea poisoning:

  • Do not plant hydrangeas in your garden if you have cats.
  • If you do have hydrangeas in your garden, keep them out of reach of your cats.
  • Trim any hydrangea branches that hang over your fence or patio.
  • If you think your cat may have eaten hydrangea, watch for any of the symptoms of poisoning and contact your veterinarian immediately.


  1. Can Hydrangeas Kill Cats if Ingested in Large Quantities?
    • While hydrangea toxicity cats, fatalities from accidental ingestion are rare. However, it’s essential to seek immediate veterinary care if you suspect your cat has ingested a large amount.
  2. How Much Hydrangea Ingestion is Dangerous for Cats?
    • The level of toxicity depends on various factors, including the cat’s size, the amount ingested, and the specific hydrangea species. Any ingestion should be taken seriously, and veterinary advice should be sought promptly.
  3. What Are the Symptoms of Hydrangea Poisoning in Cats?
    • Symptoms may include vomiting, diarrhea, lethargy, and difficulty breathing. In severe cases, cats may experience a rapid heart rate and collapse.
  4. Can I Keep Hydrangeas and Cats Separated to Ensure Safety?
    • It’s best to exercise caution and prevent cats from accessing hydrangeas altogether. Even with separation, curious cats may still find a way to interact with the plant.
  5. Are hydrangea toxic to cats?
    • Yes, hydrangeas are toxic to cats. All parts of the hydrangea plant contain a chemical called cyanogenic glycoside, which can be converted to cyanide in the body. Cyanide is a poison that can cause a number of symptoms, including vomiting, diarrhea, difficulty breathing, and seizures. In severe cases, cyanide poisoning can be fatal.
  6. Can I Train My Cat to Avoid Hydrangeas?
    • Cats can be trained, but relying solely on training to keep them away from potentially toxic plants may not always be foolproof. Preventive measures are crucial.


In conclusion, hydrangeas can be toxic to cats, and it’s crucial for cat owners to be aware of the potential dangers. While cases of severe poisoning are rare, it’s better to err on the side of caution and prevent access to hydrangeas altogether. By opting for cat-safe plants and creating a feline-friendly environment, you can ensure your cat’s well-being and enjoy a beautiful garden together. Remember, your cat’s safety is in your hands, and being informed is the first step towards responsible pet ownership.

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