Yes, Butterfly Iris is toxic to dogs!
Dogs accidentally consuming the Butterfly Iris 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).
Butterfly Iris consumption is also toxic to Cats and Horses.
Toxic Principles Of Butterfly Iris: Pentacylic terpenoids (zeorin, missourin and missouriensin).
More Info About The Butterfly Iris Plant
Scientific Name: Iris spuria
Family: Iridaceae.
Also known as: Spuria Iris.
The answer is based on information found on The American Society for the Prevention of Cruelty to Animals (ASPCA) website.