Non-blooming Trumpet Creeper vine.
My trumpet creeper is 8 years old and is very vigorous, but has never bloomed. It is on the south side of my shed and has climbed about 12 feet. It has lots of nice leaves but doesn't bloom.
Certified GKH Gardening Expert
This has two main causes. This can happen when there is too much nitrogen in the soil, or the pH is too low. You can offset this by adding a bloom formula, which will have potassium and phosphorus, but little or no nitrogen. If you believe your soil is very fertile already, and just a low pH, then you can add dolomitic lime to raise the pH. If that does not help within a year, then you will have to add fertilizers.
This article will help you on the care of these: https://www.gardeningknowhow.com/ornamental/vines/trumpet-vine/growing-trumpet-vines.htm