Vinca, also called common periwinkle, is a low growing annual plant with small five-petal flowers that are most commonly purple or white, though pink, rose and red are also found. It is an annual that self propagates from seed and can spread quickly. Vinca grows best in full sun but can adapt to partial shade. The pretty flowers and dark green leaves makes vinca popular as a flower garden border or planted in pots on a sunny deck or patio. Plant several colors in the same pot and enjoy a bright array of flowers.
Clip the seedpod from each stem when it turns from green to a light tan color. The seedpods are between 1.5 and 2 inches long and are found just under the flower in the fall.
Slit open the seed pot using a thin sharp knife. Cut along the seam, being careful not to damage the single large oblong seed inside.
Place the seeds on a paper towel in a sunny place for two to three weeks. Seeds must be completely dry before storage to prevent molding. The seedpods can be discarded.
Put the seeds in a paper bag and store in a cool dry place for the winter. A temperature of 40 to 45 degrees F is ideal for seed storage.
Remove your vinca seeds from storage in the spring when the last frost has passed. Plant them in the ground in a cool shady place or in pots for your porch or deck.