Yes, Staggerbush is toxic to dogs!
Dogs accidentally consuming the Staggerbush 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).
Staggerbush consumption is also toxic to Cats and Horses.
Toxic Principles Of Staggerbush: Grayanotoxins.
More Info About The Staggerbush Plant
Scientific Name: Lyonia sp.
Family: Ericaceae.
Also known as: Fetterbush, Maleberry.
The answer is based on information found on The American Society for the Prevention of Cruelty to Animals (ASPCA) website.