There are a few ways to propagate vinca (Catharanthus roseus), including by collecting the seeds. You can take stem cuttings in the late spring or early summer. To collect the seeds, wait until the end of the season when the petals fall off the flowers and you will see the seed pod at the base of the flower. Cut the pods off and store them in a dry, dark place for a few weeks until they dry out. After that you can shake the seed pods over paper to remove the seeds and store them in an envelope in a dark cool place.

One thing to keep in mind is that while the vinca species will grow well from seed, the fancy new cultivars will not. A cultivar seed can develop in to a plant that resembles any of its ancestors (like people) and may not have any of the characteristics that you admire in the plant.

Courtesy of NYBG Plant Information Service