How hardy is geranium Silver Cloak

I have several plants of this geranium which I grew from seed. However, I can't find any information
on it's hardiness. I live in the US, zone 6. I have an idea I'll have to winter it indoors but would like to
hear from anyone who is growing it.

I'm not growing this plant, but since the G. Silver Cloak is a crossing between the G. robustum and G. incanum, who are both from South Africa, I suppose it won't be hardy in zone 6.
May I suggest to bring some inside for winter and leave 1 or 2 outside to see if they survive.

Jonna

Thank you Jonna. With South African parents this plant will not survive our
winters. A sunny window in the basement should do it as long as I remember
to water.