You may want to cut back on the fertilizer as that might encourage rampant vine growth more than flowering at this point. Since they bloom on new growth, that growth needs to mature enough to begin flowering and onces it starts flowering, it will keep on going the rest of the summer through to frost. Give it some time!

Hi, Jenny is right. They love heat and even though I am in North Texas and it is HOT, HOT HOT, the vines I overwinter are just now grudgingly beginning to bloom. Once they start they will bloom until frost though. The one I bought which was forced by the nursery and was blooming has been blooming for a month--but the others are just now getting their first buds and it is July 7. They are very much summer vines.
Betsy