P.s. Don't fertilize trumpet vine. That will encourage leafy growth instead of blooms.
It needs some direct sunlight to bloom. It will have leafy growth in shade. If it is an old plant, try cutting half the stems to the ground this fall or winter. That may re-invigorate it. More tips are here: https://www.gardeningknowhow.com/ornamental/vines/trumpet-vine/pruning-trumpet-vines.htm