In article , nemesis7
@mindspring.com says...
A year ago spring, in S. Florid, I planted two troupe vine plants at
the base of a fan trellis. Last summer they grow about 6 feet and did
not blossom. I felt that was probably normal for the first year. This
year, the vines won;t stop growing, I have to keep cutting them back.
However, I can't find a single bud on them.

Anyone know why?

The short answer - because you keep cutting them back.
Trumpet vines like to climb tall trees and bloom in the top.