I have an established trumpet vine that has been flowering much less the last couple of summers. How many hours of sun a day are optimal for them? One problem may be a tree that has grown larger and may be blocking some sunlight, but even the parts of the plant not near the tree are showing less flowering. Would feeding it help?
Certified GKH Gardening Expert
Trumpet Vine does prefer full sun but can grow in a partial sun location. 6 to 8 hours of sunlight is considered full sun.
Here are some articles that will help with care information and helping promote flowering.