What later flowering plants can I put in a raised bed?

I have a raised bed that is planted woth roses at the back. In front of them are anenomes that have died down now, what do you recommend planting to fill the bed that is late flowering and low growing? Low growing perennials preferred. Has to be frost hardy.

FlowersBirthday FlowersSympathy FlowersCocosmia hybrids or knifofia (red hot pokers, you can get dwarf varietys), i think i spelt it right lol.puppy teeth