I planted a hummingbird vine 4 yrs ago. The vine is very healthy and aggressive, but has not bloomed one flower in the 4 yrs. Is there anything that needs to be done to help it bloom?
How Long Does It Take for a Hummingbird Vine to Bloom
Certified GKH Gardening Expert
One possibility is that the plant may be receiving too much nitrogen from lawn fertilizer.
If you think this could be the case, avoid fertilizing the lawn within 10ft of the vine.
If you don't think this is an issue, I would suggest adding a slow release high in phosphorous fertilizer in early spring.
This could be labeled at 'bloom booster' in the garden center.
This may help the plant get started blooming.
Here is a link about trumpet vine.