Are hydrangeas poisonous to cats? Symptoms, risky parts and what to do
Hydrangeas contain cyanogenic glycosides that release cyanide when chewed, affecting how cells use oxygen. While serious poisoning is uncommon in cats (obligate carnivores with little interest in plants), curious kittens and indoor cats can suffer upset stomachs or worse. Every part of the plant, especially flower buds and young leaves, poses a risk and should be kept away from cats.