I have been buying them & tossing them for about 20 years. I have always had them in full sun in a container & they seem to like it that way. My Vigna caracalla plants are coming back too. I am so happy. I love the smell when they bloom & they are cool looking too. Another full sun container plant here. Linda

Once you initially wrap one shoot around the trellis, it will continue to do it itself, but you have to start it. Place in full sun and dont cut or pinch anything back. I dont fertilize my mandevilla, it doesnt seem to need it. But I think as long as you place in full sun and have it working up a trellis it will do well.

I prune mine back when I bring it inside for the winter, so I can't imagine that it will be a problem to prune yours relatively hard. Mine have regrown from stem buds.

If its the soft leafed Alice Dupont I would wait until spring. But,for you and total frost free weather- and this warm winter- you could do that. In the bay area that is very marginal. The other "Little Red Riding Hood" often confused with Alice Dupont does great here-hardy to 10a. If you want that Alice Dupont though to climb,you should just tie the branches up neatly until longer days gets it going. I mean,cutting it back will just cost you a nice show all summer. A photo would help!