I think that part of the deal is that Michigan, while cold in winter, is blazing hot in summer or so it seemed to me in 1968 when I briefly lived there. It was in the upper 90's (Clare, Michigan) and low 100's and just coming from Alaska I was sure I would expire. Took showers then needed to towel off within minutes of getting out and NOT from the shower. That kind of weather would cause any plant to take off with a shot.
