Answer: Your mandevilla is probably the 'Alice DuPont' variety. These are very tropical in their growing requirements. While you may get away with mulching it over winter (in a winter such as the last one we had), or in a very protected location near your home, I wouldn't want to bet on that working long-term.
One option is to plant the vine in a 2 1/2 gallon nursery pot (with holes in the bottom for drainage) and sink the pot into the soil in the desired location. Roots will grow out of the holes in the bottom of the pot and the plant will establish well during the warm growing season. You could also sink a small fan shaped trellis in the pot for the vine to climb on (choose one small enough to be moved inside with the pot in winter).
In late fall, dig the container and trim off roots emerging from the holes. Also trim back the vine enough to make it manageable. Then place the container in a larger decorative pot for moving inside to a very bright location. You can mulch the surface with a little spaghnum moss to hide the fact that there is an ugly nursery pot inside the decorative container!
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