Mine are starting to show signs of life, so I wouldn't give up hope. It will grow back from the roots.
We also had a cold winter, but these plants are hardy in colder climates than you or I, so if they don't come up and have died, I doubt it was the cold that did it.
Good luck!
Barb

Barb, so there is hope still. It is still quite firm just at soil level. I have some seeds germinating as a back-up though.

I had intended planting it outside this year. Any advice. Clay soil with high Ph, hope it will flower with regular watering.

Many thanks,
Maria

It like moist conditions, so I would imagine clay soil won't deter it. I haven't heard about pH affecting them one way or another; perhaps some others here can add something about that.
I know the seeds have a high ghermination rate so if all else fails, you will have plants this summer!
Barb