Bellis perrenis 'Blushing bride'

I planted some Bellis Perenis 'Blushing Bride' this year. The instructions said to sow direct, but as my borders have gravel on I sowed then into pots. Is it too late to plant these out or would it be better to leave them in the cold frame until spring?

Rusty

 

Never grown them Rusty - but with this very cold weather I would certainly keep the pots in a cold frame overwinter.