More than 400 million barberry bushes were eradicated in 1920s.

Evidence

More than 400 million barberry bushes were rooted out by Stakman’s diggers in a swath covering eighteen states. — Nicholson Baker, Baseless- My Search for Secrets in the…, 839

Categorization

• corroborated: 3 independent passages support this claim — Nicholson Baker, Baseless- My Search for Secrets in the…, 839