I live in zone 6,
I planted Mandevilla’s on side of my Mailbox facing north… pretty much all day sun
plants grew with no problem (in ground)
This year planted in same location, but one exception, I placed in pots so it would be easier to bring in house for winterization..
My question is: Why I did not get vines, but plenty of flowers… plant looks very healthy. puzzled.
This article will help with care information.
There are new varieties that are grown to be a more compact plant, for hanging baskets.
Over time your plant should grow vines.