I purchased 4 Violet Trumpet Vine plants and planted them in a raised bed that I have built on the side of our garden shed.
The problem is that none of them have grown at all within 4 months (since September).
I used a wooden trellis and tied the vines to the trellis. The plants are bedded in general-purpose soil and I used cardboard as a weed barrier.
The first two weeks I (hand) watered them daily, then I switched over to watering them once a week, until the winter rains started setting in.
Based on their position, they get about 5 hours of direct sunlight and indirect sunlight for the rest of the day. I am located in Northern California (zone 9).
So far, I haven't tried fertilizer as the nursery hasn't recommended using any, as long as the soil is good quality.