We are going to build a pergola this summer. I love trumpet vines on pergolas. Since I live on the Wisconsin/Illinois state line, ( supposedly zone 4b/5a) would a trumpet vine be hardy if I planted it in a large (20 inch, at least) pot and left said pot outside during the winter? I do have a greenhouse, so I could prune the beast back hard and put it in for the winter, or do they need a cold/dormant time? I really don't want to plant one in the ground because I know they can overtake an area in a short time. (think "The Trouble With Tribbles..........") LOLOL
