It would have to be a heated greenhouse here. We have very cold brutal winters. Too much $$ for us... although I used to dream of one when I was younger. I have a cold frame for early spring use, but it is low and mostly for seedlings. The impatiens won't fit at all.

I am used to the impatiens dying in late fall. This year though they are just so spectacular, I've grown attached to them.

I used to have a big barrel across the street with them, until the wood rotted out. I stopped doing them there, but one year they lasted until late November! The creek here across the street does moderate frosts some in fall, but our weather has been so extreme this season...either blistering hot, or brutally cold, it is hard to say what will happen this season.