We call them burrdock:

Arctium lappa

greater burrdock; great burdock; edible b.; harlock; cuckold

Species Record #: gw1002500

Botanical Information:

Genus: Arctium

Family: Compositae

Author: L.

Synonyms: Lappa major

Remarks:
Plant trivia: The burrs on this plant are probably the ones that inspired Swiss engineer George de Mestral, the inventor of Velcro (TM).