It will probably be okay in your zone, but it will be dicey here in zone 3.
If I get germination, I will be placing the hubrichtii up nearer the house.
The tracheamontana variety is hardy to zone 3 according to my searches.
I am doing these as a wintersow.
Caroline zone 3 Calgary

Ansonia hardiness is discussed in "A book of Blue Flowers"
by Robert Geneve (Timber Press).
He says the amsonia tabernaemontana is hardy to -40ºC (-40ºF)
and the other species to -29ºC ( -20ºF).
So I may luck out with hubrichti and jonesi as well as the tabernaemontana.
I have done them as a winter sow.

I found the first year to be our big challenge.I am a zone 4-5 in northwest Montana.In the colder years if not established it died off.In our warmer years it did real well and as it established it has grown into some nice plants.Not sure if this helps since I am right in the center of the zones listed.

We shall see---it will depend on the kind of springs we experience.
I will post my experiences---but I do not expect flowers until year two.

I am zone 5a. I've had it live thru the last 2 winters .
Karen