Flowers are one nighters. After the flower drops, a seed pod will appear, allow it to dry on the vine till you can hear the seeds rattle when you shake it. Then open the pod and save the seed. I had my first moonflower vine last year and got alot of seed. Have about a dozen started for this year, they grow like crazy. When you are ready to start your seeds next year, nick the pointy end and soak for 24 hours.