Question
Is it possible to harvest seeds from the annual vinca minor
flowers, and if so, how do I do it?

Answer
To harvest seed, you must let the spent flowers die off naturally and form a small seed pod. Once the seed pod begins to turn brown, you want to cut it and place it in a paper bag for a few days to dry out. Then transfer the pods to a ziplock bag, seal it, and place it in a sealed tupperware container in the back of the refrigerator. The seeds must go through a dormancy period of at least three months. Late next winter, you can remove the seeds from the pods and sow them in small pots or wait to sow them directly in the garden. Given their longer than average germination period, I would start them indoors and transplant them outdoors once the last chance of frost has passed.

I hope this answered your question. Good luck, and please write again if I can ever provide assistance.

Regards,

Mike