Mandevilla varieties x M. laxa for improved cold tolerance?
I really love the beautiful flowers of all types of Mandevilla, but unfortunately for me the only one I've found capable of surviving outdoors year round in my climate is Mandevilla laxa. So I was recently wondering if anyone has ever tried crossing this with any of the other varieties with the aim of introducing improved tolerance to cold into the progeny? Is this possible/worth trying or not?
Would like to hear peoples opinions on this, especially if you could explain why it won't/might work out and any ideas that might increase the chances of success.