Alex, I grow Calandrinia spectabilis too. In my area with our mild winters, I can leave it outdoors year round. Needs bright light to full sun to have blooms in Spring to early summer It goes on semi-dormancy during our very hot summer days. . And then comes back again with new growth during late Fall to winter. It actively grows in winter, and can take our occasional winter rains, as long as I make sure the media has very good and coarse drainage.
But then again our cold winter temps may be just a walk in the park for your area...
But that plant likes to feel cool as it wakes up from its summer sleep.
I do agree that 17F is really too cold for most plants. At the most, some succulents can bear the cold if protected by an overhang or planted as close to the house as possible so it can benefit from the heat from the house, or some like semps can be more insulated by snow cover. Cold and dry okay for some succulents. Cold and wet ...goodbye succulents..
