I am growing an orange trumpet vine on an arbor in my backyard. This is my third season with it and still no flowers. It comes back every year and grows and grows but no blooms. Needless to say I am very disappointed as I wanted it especially for the hummingbirds!
Why Won’t My Trumpet Vine Flower?
Certified GKH Gardening Expert
It sounds like it has too much nitrogen, which is common for these fast growing vines, especially of they are near a lawn that gets fertilized (lawn fertilizer is high in nitrogen). Try root pruning with a shovel. Drive a shovel into the ground in a circle around the plant about 3-4 feet away from the plant. This will prune the roots and it won't be able to take in as much nitrogen, which will allow it to bloom.
If it is planted near a lawn, in the future, don't fertilize near the plant if possible.
This article will have some other suggestions: