Mine sure won't bloom if I let them get that cold. I enclose them in a frost cloth tent to keep the ambient temp around the plants above 50 or so. The cloth traps the warmth rising from the ground and protects from the cold wind. Then they will keep putting on buds.
But a couple of winters we were away when the temps dropped, and all the brugs sulked until well into March when it was getting a lot warmer again.
