I wouldn't worry too much as moonflowers and a number of their cousin morning glories don't bloom until quite late in summer here, if they bloom at all. These are a semi-tropical vine in origin and need a full 6-8 hours of sun and hot weather to bloom. Unfortunately, our summers don't often measure up in the heat index department :-( Go ahead and start over with the seeds and when ready to plant, make sure you have them sited in a location that gets reflected heat to beef up the temperatures. Good luck!

I planted seeds once, it was in early April and there were a few blooms by mid to late August thru September, you have to stay up late or get up really early to see the flowers! I had my sprouts in a mini-greenhouse for a month or so before planting out in late May.

I think there was one flower every three days for a while, far fewer than regular morning glories.