Oh, golly. Hope it isn't...giant hogweed. http://www.ontarioinvasiveplants.ca/files/HogweedLookAlikes.pdf
Ditto to Tyrlych; Seseli gummiferum looks a good bet: http://commons.wikimedia.org/wiki/File:Seseli_gummiferum_habitus1.jpg and is sold as a garden plant.