In article , Roy Bailey
writes

Greater and Lesser Burdocks - Arctium lappa and A.minus are biennials.
Thank God for that! I was beginning to fear that they were perennials.

They give that impression by re-seeding themselves. They are a much
prized wild flower in some people's estimation but if you really want to
be rid of them, remove all flower heads before they mature.
--
Alan & Joan Gould - North Lincs.