Hydrangeas are some of the most beautiful and popular flowers found in British gardens. With their large blooms in shades of blue, pink, red and white, they are a favourite for many gardeners. But experts have now warned that these plants come with a hidden danger.

According to veterinary experts at PetMD, hydrangeas are toxic to dogs and cats. Every part of the plant, including the flowers, buds, leaves and stems, contains a chemical called amygdalin, which can cause serious health problems if ingested. Amygdalin is a cyanogenic glycoside, the same type of compound found in apple seeds and cherry pits. 

When chewed and digested, it releases cyanide, which can make it difficult for an animal’s body to absorb oxygen.

PetMD says symptoms of poisoning can start within just 15 to 20 minutes if a large amount is eaten. 

These include rapid breathing, drooling, muscle spasms, vomiting, diarrhoea, and even bright red or blue gums. 

Smaller dogs are especially at risk because even small amounts of the plant can be harmful to them.

More common signs of a mild reaction include lethargy, vomiting, diarrhoea, and a loss of appetite.

These may be easier to treat, but PetMD still recommends speaking to a vet immediately if you suspect your dog has eaten any part of a hydrangea plant.

“If a large amount of the hydrangea plant has been ingested, time is of the essence,” PetMD warned. “Toxicity will worsen as your dog continues to absorb the toxin.”

They added: “Call your veterinarian or the Pet Poison Helpline if your dog has ingested any amount of any part of the hydrangea shrub.”

Treatment will vary depending on how much your pet has eaten and how serious the symptoms are. 

In milder cases, a vet may prescribe anti-nausea medication and antibiotics to treat diarrhoea.

Probiotics may also be recommended to help your dog’s gut recover.

If the dog is severely unwell, it may need to be hospitalised for IV fluids, oxygen therapy, and monitoring. 

In some cases, vets may try to induce vomiting, but this should never be done at home.

The good news is most dogs recover quickly once the toxin has left their system. 

However, in extreme cases where the body absorbs too much cyanide, the situation can become life-threatening.

To prevent hydrangea poisoning, PetMD advises dog owners to keep pets away from any area where hydrangeas grow, whether in the garden or indoors.

They added: “Many dog lovers also love flowers and plants. Know which plants are safe and which are not, so that you can keep your pup safe.”