How to overwinter rudbeckia?

Yo. So I’ve been slowly filling a border with perennials and I like to make the most of buying plants out of season from a local garden centre at reduced prices. Today I picked up 3 rudbeckia, amongst other things, but hadn’t realised they are only half hardy so if we have a harsh winter they may not even make it to next year if I put them in the ground?

I’ve never had them before so I’m looking for your experience with them. I’m in the SE and have a greenhouse.