I left this plant outside through a frost and even a little snow. Still it kept the purple blooms. I brought it inside and replanted it. We'll see if it lasts, but I'll give it a chance. It earned it.
Once, a branch broke off my tomato plant. It was the only branch with any blooms on it, so I stuck it in a jar of water. 2 years later, it finally met its demise, but it had grown and bloomed that whole time in a jar. I love my stubborn plants.