Which varieties are you growing?

Heavenly blue, milky way, crimson rambler, ipomoea alba(moon vine) and cypress vine mix.

Site the containers somewhere where they will receive a lot of reflected heat - on a concrete or stone patio, a driveway, against a west or south facing wall. It doesn't often get hot enough in western WA in summer for these vines to flourish and bloom well. We get good growth......but not so much the flowers :-)

I have a long driveway with south facing walls.
Sounds like that is the spot for heat loving vines.
I put some MG's into nursery pots and strung them up against the south facing garage wall. We will see what happens.

Milky Way, Crimson Rambler and Cypress Vine should make flowers before the other two. Ensure your soil drains well. That is useful information about reflected heat. Does it stay cool at night during the summer where you live?