Yes, Gladiola is toxic to dogs!
Dogs accidentally consuming the Gladiola plants can show the following clinical symptoms: Vomiting, Prolonged Depression, Incoordination, Hypersalivaton, Sleepiness Or Excitation, Dilated Pupils, Low Body Temperature, Low Blood Pressure, Coma, Seizure And Death (In Rare Cases).
Gladiola consumption is also toxic to Cats and Horses.
Toxic Principles Of Gladiola: Unknown.
More Info About The Gladiola Plant
Scientific Name: Gladiolus species
Family: Iridaceae.
Also known as: Many cultivars.
The answer is based on information found on The American Society for the Prevention of Cruelty to Animals (ASPCA) website.