This is my first year with a greenhouse. I couldn't be happier with it. I say, if it's too cold for me then it's too cold for the plants. I'm cold today!! Though we don't usually get as tough a winters as most, this year has been colder than normal for us. I am sure the plants are happy with the temporary structure. We are struggling to reach 50º right now. But the sun is out. So both ends of the greenhouse are open for sun and air circulation. But the heater is still on. They fair far better than they did in the garage. Yet, with limited space in the greenhouse, there are a lot of plants in the garage still. I will have to remember to put the bougainvialla in the gh, as they struggle each winter in the garage with not enough sunlight. But every spring they come back. DD used to live in Summerville, then Goose Creek. You do get some cold temps out there, Anne. A lot colder than Houston. Do your Butterfly Bush flowers have a scent?? A scented flower in a warm greenhouse sounds very inviting!