I personally wouldn't plant any herbaceous plants until its a bit warmer principally because I wouldn't be sure if they had been hardened off properly

You would need a pick axe to get into our soil at the moment. I would leave them in their pots for while yet and certaily not plant in frosty weather. If the soil is soft you could try plunging the pot for now and planting properly later - just don't forget that this is what you have done!

Put the pot on a table in the garden to enjoy the blooms for now.

but while we're having these sharp frosts I'd put the pot in a sheltered spot overnight